Crea sito

## Result for K-Tuples of Primes

The competition K-Tuples of Primes is over.

Thanks to all people that have partecipate.

The winner is Jarek (see Ranking)

The result is in this table:

[insert_php]

include_once “pmg/pmg.php”;

echo pmg_db_get_result(4);

[/insert_php]

Here are the best solution arrived after the ending of the competition:

[insert_php]

echo pmg_db_get_result_extra(4);

[/insert_php]

## Ranking for K-Tuples of Primes

This is the Ranking of the K-Tuples of Primes competition:

[insert_php]

include_once “pmg/pmg.php”;

echo pmg_db_get_classif(4);

[/insert_php]

# Competition #4

This competition is organized by Макарова Наталия (Natalia Makarova)

## Definitions

### Definition 1:

A prime k-tuple is a finite collection of values (p + a1, p + a2, p + a3, …, p + ak), where p, p + a1, p + a2, p + a3, …, p + ak are prime numbers, (a1, a2, a3, …, ak) are pattern. Typically the first value in the pattern is 0 and the rest are distinct positive even numbers.

We consider the k-tuple, where p + a1, p + a2, p + a3, …, p + ak are consecutive primes.

### Definition 2:

k-tuple (p + a1, p + a2, p + a3, …, p + a [k / 2], p + a [k / 2+1], …, p + a [k-2], p + a [k-1], p + ak) for k even, is called symmetric, if the following condition is satisfied:
a1 + ak = a2 + a[k-1] = a3 + a[k-2] = … = a[k/2] + a[k/2+1]

Example: symmetric 8-tuple

`(17 + 0, 17 + 2, 17 + 6, 17 + 12, 17 + 14, 17 + 20, 17 + 24, 17 + 26)`

Shortened we write this:

`17: 0, 2, 6, 12, 14, 20, 24, 26`

### Definition 3:

k-tuple (p + a1, p + a2, p + a3, …, p + a [(k-1) / 2], p + a [(k-1) / 2 + 1], p + a [(k-1) / 2 + 2], …, p + a [k-2], p + a [k-1], p + ak) for k odd called symmetric, if the following condition is satisfied:
a1 + ak = a2 + a[k-1] = a3 +a [k-2] =…= a[(k-1)/2] + a[(k-1)/2+2] = 2 a[(k-1)/2+1]

Example: symmetric 5-tuple

`18713: 0, 6, 18, 30, 36`

### Definition 4:

The diameter d of k-tuple is the difference of its largest and smallest elements.

Example: 8-tuple

`17: 0, 2, 6, 12, 14, 20, 24, 26`

It has a diameter d = 26.

### Definition 5:

A pandiagonal magic square is a magic square with the additional property that the broken diagonals, i.e. the diagonals that wrap round at the edges of the square, also add up to the magic constant.

## The Contest

In the contest is required to compete for those tasks:

Required to find k-tuples with the minimal value p:
for an even k > 24; for odd k > 15.

Example

```15-tuple, p=3945769040698829 (minimal)
3945769040698829: 0, 12, 18, 42, 102, 138, 180, 210, 240, 282, 318, 378, 402, 408, 420```

Required to find k-tuples with a minimal diameter d:
for an even k > 10; for odd k > 13.

Example
8-tuple with a minimal diameter d = 26

`17: 0, 2, 6, 12, 14, 20, 24, 26`

Required to find the 16-tuple, the elements of which it is possible to make pandiagonal magic square of order 4 with magic constant S as: 94615738903617540 < S < 29643562211780078520 Example 16-tuple

`23653934725904299: 0, 12, 22, 34, 48, 60, 70, 82, 90, 102, 112, 124, 138, 150, 160, 172`

pandiagonal magic square

```23653934725904299+
0  160   60  124
82  102   22  138
112   48  172   12
150   34   90   70

S=94615738903617540
```

### Rule:

Prime numbers can contain no more than 100 digits.

In tasks 1 and 2 k <= 50.

## Format of solution

For every task the first line is the number of task you are entering: so 1, 2 or 3. After there are those lines according to the tasks you are inserting.

In tasks 1 and 2

k-tuple is represented as

`p: a1, a2, a3, …, ak`

Example

`18713: 0, 6, 18, 30, 36`

it is 16-tuple and pandiagonal magic square of order 4, composed of the elements of the tuple.

Example

```23653934725904299: 0, 12, 22, 34, 48, 60, 70, 82, 90, 102, 112, 124, 138, 150, 160, 172
0, 160, 60, 124, 82, 102, 22, 138, 112, 48, 172, 12, 150, 34, 90, 70
```

## Scoring

The contestant receives one point for every solution to tasks 1 and 3.
For each k in task 2 one point counted towards only those participants, who will have a minimum diameter d.

## The Prize

If two or more contestants have equal number of points, the winner will be the entrant who submitted solutions ahead of other contestants.
The winner will receive a prize of 5,000 rubles.
If the winner is not from Russia, the prize will be paid in US dollars at the official exchange rate on the day ending of the contest.

## Thanks

We thanks  Wolfram Alpha as we use their API for testing the primality of the given big numbers.

## Result for Ultra Magic Squares of prime numbers

The competition Ultra Magic Squares of prime numbers is over.

Thanks to all people that have partecipate.

The result is in this table:

[insert_php]

include_once “pmg/pmg.php”;

echo pmg_db_get_result(3);

[/insert_php]

Here are the best solution arrived after the ending of the competition:

[insert_php]

echo pmg_db_get_result_extra(3);

[/insert_php]

## Ranking for Ultra Magic Squares of prime numbers

This is the Ranking of the “Ultra Magic Squares of prime numbers” competition:

[insert_php]

include_once “pmg/pmg.php”;

echo pmg_db_get_classif(3);

[/insert_php]

# Competition #3

This competition is organized by Макарова Наталия (Natalia Makarova)

## Definitions

### Definition 1:

Magic square is called ultra magic square, if it is both associative (center symmetric) and pandiagonal.

Ultra magic squares exist for orders n > 4.

## The Contest

In the contest is required to built ultra magic squares of order 7 – 16 of distinct primes.

Example

```n = 5

113 1151 1229  911  101
839  521   41 1013 1091
941  953  701  449  461
311  389 1361  881  563
1301  491  173  251 1289

S=3505
```

This is the minimal solution for n = 5.

Known as a minimal solution for n = 6 (author M. Alekseyev)

```103  59 163 233 139 293
229 257 307 131  13  53
283  17  67 173 181 269
61 149 157 263 313  47
277 317 199  23  73 101
37 191  97 167 271 227

S=990
```

### Rule:

For each order n = 7 – 16 you can imagine several solutions with magic constants S1 <S2 <S3 …

Known solutions:

```n = 7, S = 4613 (author N. Makarova)
n = 8, S = 2640 (author N. Makarova)
n = 9, S = 24237 (author A. Chernov)
```

Contestant shall not be deemed a winner, if he would submit only solutions with known magic constants

## Format of solution

The solution is represented in the form:

n: a (1), a (2), a (3), …, a (n^2)

Example:

```5:113,1151,1229,911,101,839,521,41,1013,1091,941,953,701,449,461,311,389,1361,881,563,1301,491,173,251,1289
```

## Scoring

Contestant receives for every n the score: Smin/S, where

Smin – the minimal magic constant of solution in the contest;

S –  the minimal magic constant of solution by contestant.

## The Prize

Winner receives a prize of 3000 rubles.

If the winner is not from Russia, the prize will be paid in \$USA at the official rate on the day of end the contest.

Organizers N. Makarova and S. Tognon can participate in the contest, but does not receive the prize in case of winning.

## Result for Pandiagonal Squares of Consecutive Primes

The competiotion was termanated without inserted result and with no winner (the two values in ranking are just testing result).

Remember that you can still try to find new solution for the problems (without price) and in that cases the result will be presented here.

Thanks

## Ranking for Pandiagonal Squares of Consecutive Primes

This is the Ranking of the “Pandiagonal Squares of Consecutive Primes” competition:

[insert_php]

include_once “pmg/pmg.php”;

echo pmg_db_get_classif(2);

[/insert_php]

# Competition #2

This competition is organized by Макарова Наталия (Natalia Makarova)

## Definitions

### Definition 1: Pandiagonal magic squares

Magic square is called pandiagonal, if the sum of the numbers in each of the broken diagonal is the magic constant of the square.

For example – pandiagonal square of order 8 of prime numbers:

```  5   13  463  293  443  283   53   31
313  379   71   73   89   79  191  389
23  211  167  331  199  353  149  151
449  239   41   97   59  127  349  223
19   47  439  269  457  317   29    7
241  383  109  103   17   83  229  419
101  139  181  311  277  281  163  131
433  173  113  107   43   61  421  233

Magic constant of the square S = 1584
```

## The Contest

In the contest is required to construct pandiagonal squares of consecutive primes.
It is necessary to solve the problem for the orders n = 4 – 10.

### Rule:

Basic rule: solutions with known magic constants are not accepted.
n=4: Required to find solutions with magic constant S > 682775764735680
n=6: Required to find solutions with magic constant S > 930

### Known solutions

1. n = 4 (minimal, author Max Alekseyev)
```170693941183817+
0     116  132  164
162 134   30    86
74   42     206  90
176 120   44    72

S=682775764735680
```
2. n=4 (authors J. Wroblewski and J. K. Andersen)
```320572022166380833+
0   88  16  84
76 24  60 28
78 10  94 6
34 66 18  70

S = 1282288088665523520
```

Required to find solutions with magic constant S > 682775764735680.

3. n = 6 (minimal)
```67+
0 126 4 184 42 172
72 166 46 114 90 40
174 30 124 22 96 82
6 100 64 162 84 112
132 36 160 34 60 106
144 70 130 12 156 16

S=930
```

Required to find solutions with magic constant S > 930.

4. For the orders n = 5, 7 – 10 unknown solutions.

## Format of solution

Solutions should be introduced in a normalized form, plus dimension.
The first line must contains the dimension of problem (4, 5..10)
The second the normalized form of solution.
For example:

```6
67: 0,126,4,184,42,172,72,166,46,114,90,40,174,30,124,22,96,82,6,100,64,162,84,112,132,36,160,34,60,106,144,70,130,12,156,16
```

## Scoring

Contestant receives one point for each new decision.
Solutions with the same magic constant are considered equal, even if they are not isomorphic.

## The Prize

Instituted a price to the participant who has won first place – \$ 100 USA.
In cases of more people will have the same final score for the first positons, the price goes to the one that makes that score before the other.
If the winner will be the contestant from Russia, he will receive a prize in rubles at the official exchange rate on the last day of the competition.

The competition was taken from 23/09/2014 to 23/12/2014 but due to no winners (no one introduce a valid solution), it is now extended just for fun and not for price.

1. https://ru.wikipedia.org/wiki/Магический_квадрат
2. https://en.wikipedia.org/wiki/Magic_square
3. B. Rosser and R. J. Walker. The algebraic theory of diabolic magic squares
4. N. Makarova. Unconventional pandiagonal squares of primes
http://www.natalimak1.narod.ru/panpr.htm
http://www.natalimak1.narod.ru/pannetr.htm
http://www.natalimak1.narod.ru/pannetr2.htm
5. Contest “Pandiagonal Magic Squares of Prime Numbers” (from Al Zimmermann)
http://www.azspcs.net/Contest/PandiagonalMagicSquares/FinalReport
6. The smallest magic constant for any n x n magic square made from consecutive primes
http://oeis.org/A073520
7. The smallest magic constant of pan-diagonal magic squares which consist of distinct prime numbers
http://oeis.org/A179440

## Result for Magic Cubes of Prime Numbers

The competition Magic Cubes of Prime Numbers is over.

Thanks to all people that have partecipate.

The winner is Natalia, but price goes to Dmitry

The result is in this table:

[insert_php]

include_once “pmg/pmg.php”;

echo pmg_db_get_result(1);

[/insert_php]

Here are the best solution arrived after the ending of the competition:

[insert_php]

echo pmg_db_get_result_extra(1);

[/insert_php]