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A156523 Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 68. 0
2, 2, 80, 404, 63392, 1572582, 1619260788, 75946691122 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Table of n, a(n) for n=2..9.

CROSSREFS

Sequence in context: A130678 A230054 A303569 * A191779 A156511 A166996

Adjacent sequences:  A156520 A156521 A156522 * A156524 A156525 A156526

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 09 2009

STATUS

approved

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Last modified January 22 10:48 EST 2021. Contains 340362 sequences. (Running on oeis4.)