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A156449 Number of nXn 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 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

CROSSREFS

Sequence in context: A059719 A066228 A110881 * A192374 A117443 A095858

Adjacent sequences:  A156446 A156447 A156448 * A156450 A156451 A156452

KEYWORD

nonn

AUTHOR

R. H. Hardin (rhhardin(AT)att.net) Feb 09 2009

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Last modified February 17 21:13 EST 2012. Contains 206085 sequences.