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A156449
Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 9.
0
1, 2, 4, 28, 68, 788, 2096, 74764, 297215, 56568904, 378230514, 110049447136, 1117730631388, 399699792848864, 6285859127170900, 2788382742936560544
OFFSET
1,2
CROSSREFS
Sequence in context: A227303 A066228 A110881 * A259375 A192374 A274526
KEYWORD
nonn
AUTHOR
R. H. Hardin Feb 09 2009
STATUS
approved