A191679 -id:A191679 - cp's OEIS frontend

A189188 Potential magic constants of 8 X 8 magic squares composed of consecutive primes.

2016, 2244, 2336, 2570, 2762, 4106, 4362, 4464, 4566, 4670, 4776, 4934, 5952, 6870, 7036, 7146, 7588, 7644, 7700, 8824, 9756, 9930, 9988, 10394, 10454, 10514, 10690, 10868, 10928, 11560, 12620, 12682, 14986, 15424, 15808, 16000, 16510, 18668, 20434

Offset: 1

Natalia Makarova, Apr 18 2011

nonn

For an 8 X 8 magic square composed of 64 consecutive primes, it is necessary that the sum of these primes is a multiple of 16.
This sequence consists of even integers equal to the sum of 64 consecutive primes divided by 8. It is not known whether each such set of consecutive primes can be arranged into an 8 X 8 magic square but it looks plausible.
From A.H.M. Smeets, Jan 20 2021: (Start)
Except from the condition that a magic constant exists, it must be an even magic constant due to the fact that the order is even, which explains why the sum of primes must be divisable by 16.
The number of possible combinations of 8 primes out of the 64 consecutive primes added results in the magic constant is such that in almost all cases such a magic square existsts. However, as n increases, the diversity in prime gaps between the 64 consecutive primes increases, and thus the probability that a potential magic constant will lead to a magic square configuration will decrease. The challenge here seems to be to find a potential magic constant which has no magic square configuration. (End)

			a(1) = 2016
  [ 79 137 197 199 277 347 349 431
   127 193 131 419 337 421 107 281
   103 379 283 389 293 227 179 163
   397 251  83 271 269 157 439 149
   409 211 383 191 181 101 401 139
   307 239 317 167  89 367  97 433
   353 233 359 151 257 223 331 109
   241 373 263 229 313 173 113 311 ]
.
a(12) = 4934
  [ 823 619 461 457 631 587 599 757
    443 563 647 509 733 761 787 491
    503 809 419 701 661 797 487 557
    683 499 743 677 449 607 617 659
    439 727 571 577 719 821 601 479
    811 641 593 523 421 467 709 769
    691 433 673 751 773 431 613 569
    541 643 827 739 547 463 521 653 ]

A.H.M. Smeets, Table of n, a(n) for n = 1..20000
Natalia Makarova Magic squares of order 8 which consist of consecutive primes (in Russian)
A.H.M. Smeets, Magic squares of consecutive primes of order 8

Cf. A073520, A173981, A176571, A177434, A188536, A191679, A192087.

s:= proc(n) option remember;
       `if` (n=1, add (ithprime(i), i=1..64),
                  ithprime(n+63) -ithprime(n-1) +s(n-1))
    end:
a:= proc(n) option remember; local k, m; a(n-1);
       for k from 1+b(n-1) while irem(s(k), 16, 'm')<>0 do od;
       b(n):= k; 2*m
    end:
a(0):=0: b(0):=0:
seq(a(n), n=1..50);

Edited by Max Alekseyev, Jun 18 2011

A192087 Potential magic constants of a 10 X 10 magic square composed of consecutive primes.

Original entry on oeis.org

2862, 3092, 3500, 4222, 4780, 5608, 7124, 10126, 10198, 11212, 11426, 12140, 12212, 12284, 12356, 12428, 12714, 12854, 12924, 15270, 16252, 16476, 18594, 18672, 18750, 18828, 19214, 20764, 21150, 23752, 24214, 24598, 24828, 27180, 27342, 27424, 27916, 28666, 29406, 29568

Offset: 1

Natalia Makarova, Jun 23 2011

nonn

For a 10 X 10 magic square composed of 100 consecutive primes, the sum of these primes must be a multiple of 20.
This sequence consists of even integers equal the sum of 100 consecutive primes divided by 10. It is not known whether each such set of consecutive primes can be arranged into a 10 X 10 magic square but it looks plausible.
Actual magic squares were constructed for all listed magic constants <= 11212.

			a(1)=2862 for a square containing prime(9)..prime(108):
  [23  179  409  373  263  137  461  457  523   37
  193  353  443  199  317  109  337  397  131  383
   71   73  389  251  593  167  439  449  233  197
  571  293  101  229   29  557  271   31  379  401
  127  419  283  241  269  239  547   89  181  467
  491  433  223  113   41  577   43  311  563   67
  281   97  163  587  191  313  149  509  421  151
  307  499  227  431  103   83   59  479  211  463
  277  359  257  331  569  541   53   79   47  349
  521  157  367  107  487  139  503   61  173  347]
.
a(10)=11212
  [769   863  1171   967   859  1381  1237  1459  1289  1217
  1163   953   797  1297  1049  1021  1303   977  1423  1229
   809  1277  1153   937  1151  1409  1291   839  1249  1097
  1429  1231  1193  1451  1061   829   821  1361   823  1013
  1453   997   947  1091  1321   887  1283   941   811  1481
  1069  1201  1427  1129   907   919  1373  1039  1117  1031
  1009  1123  1301  1093  1367  1483   911  1051  1087   787
   991  1109  1279   877  1223   929  1187  1433  1327   857
  1213  1439  1063   971  1447   883   773  1259   983  1181
  1307  1019   881  1399   827  1471  1033   853  1103  1319]

Natalia Makarova, Sequence of Magic Numbers MK 10th Order (in Russian).

Cf. A073520, A173981, A176571, A177434, A188536, A189188, A191679.

s:= proc(n) option remember;
       `if` (n=1, add (ithprime(i), i=1..100),
                  ithprime(n+99) -ithprime(n-1) +s(n-1))
    end:
a:= proc(n) option remember; local k, m;
       a(n-1);
       for k from 1+b(n-1) while irem (s(k), 20, 'm')<>0 do od;
       b(n):= k; m
    end:
a(0):=0: b(0):=0:
seq (2*a(n), n=1..50);

cp's OEIS Frontend

A189188 Potential magic constants of 8 X 8 magic squares composed of consecutive primes.

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