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A156469 Number of nXn arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 18. 0
1, 4, 54, 112, 5414, 21624, 2133044, 23029656, 5468265896, 163052061000, 97305384072800 (list; graph; refs; listen; history; internal format)
OFFSET

2,2

CROSSREFS

Sequence in context: A099340 A158259 A095210 * A001545 A073863 A199022

Adjacent sequences:  A156466 A156467 A156468 * A156470 A156471 A156472

KEYWORD

nonn

AUTHOR

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

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Last modified February 15 11:25 EST 2012. Contains 205777 sequences.