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A156436 Number of n X n arrays of squares of integers, symmetric under 90 degree rotation, with all rows summing to 4. 0
1, 0, 0, 3, 5, 12, 54, 426, 2334, 23280, 152820, 1939740, 14564760, 222925920, 1890254100, 33899743010, 320743643010, 6597891367200, 68944295861280, 1600434039456630, 18309730315533930, 473501454337711800 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,4
LINKS
CROSSREFS
Sequence in context: A291936 A307146 A293599 * A352145 A276735 A099791
KEYWORD
nonn
AUTHOR
R. H. Hardin Feb 09 2009
STATUS
approved

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Last modified March 2 15:53 EST 2024. Contains 370494 sequences. (Running on oeis4.)