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A156435
Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 4.
0
1, 2, 2, 7, 13, 110, 440, 7010, 34814, 709332, 4108632, 100368324, 667960824, 18944759304, 142719383676, 4596517872930, 38710991748930, 1392671800456580, 12976446818207108, 514918876680042334, 5262123025959154234
OFFSET
1,2
CROSSREFS
Sequence in context: A362318 A049953 A364313 * A344048 A228432 A298959
KEYWORD
nonn
AUTHOR
R. H. Hardin Feb 09 2009
STATUS
approved