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%I #40 Feb 04 2024 21:26:02
%S 240,252,288,372,408,420,480,492,504,528,540,552,560,564,576,588,600,
%T 612,620,624,648,660,672,680,684,708,720,728,732,740,756,768,780,792,
%U 800,816,828,836,840,848,852,860,864,876,888,900,912,920,924,936,948
%N Magic constants of pandiagonal magic squares of order 4 composed of distinct primes.
%C A pandiagonal square of order 4 consists of 8 pairs of complementary numbers with the sum in each pair equal to S/2 (where S is the magic constant). For example, the array {7, 113, 11, 109, 13, 107, 17, 103, 19, 101, 23, 97, 31, 89, 37, 83, 41, 79, 47, 73, 53, 67, 59, 61} consists of 12 complementary prime pairs with the sum 7 + 113 = 11 + 109 = ... = 59 + 61 = 120 = S/2.
%C Pandiagonal squares of order 4 are also the most-perfect squares.
%C There is a one-to-one correspondence between pandiagonal and associative magic squares of order 4. Any pandiagonal square can be turned into an associative square by rearrangements of its rows and columns, and vice versa.
%C For example, pandiagonal square:
%C [ 13 83 31 113
%C 97 47 79 17
%C 89 7 107 37
%C 41 103 23 73 ]
%C the corresponding associative square:
%C [ 13 83 113 31
%C 97 47 17 79
%C 41 103 73 23
%C 89 7 37 107]
%C Magic constants of pandiagonal magic squares of order 4 are always multiples of 4. It looks as though most sufficiently large multiples of 4 are magic constants of some pandiagonal magic squares of order 4. For multiples of 4 between 3000 and 10000, only 3028, 3208, 3436, 3664, 4436, 4504, and 5116 are not the magic constant of any pandiagonal magic squares of order 4. - _Zhao Hui Du_, Jan 09 2024
%H Max Alekseyev, <a href="/A191533/b191533.txt">Table of n, a(n) for n = 1..100</a>
%H Natalia Makarova, <a href="http://www.natalimak1.narod.ru/pand4.htm">Order-4 pandiagonal magic squares composed of primes</a> (in Russian)
%e a(3)=288 for the matrix
%e [ 7 127 41 113
%e 71 83 37 97
%e 103 31 137 17
%e 107 47 73 61 ]
%Y Cf. A179440.
%K nonn
%O 1,1
%A _Natalia Makarova_, Jun 05 2011
%E Terms a(18) onward from _Max Alekseyev_, May 26 2012
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