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A156429
Number of 20 X 20 arrays of squares of integers, symmetric under 90-degree rotation, with all rows summing to n.
0
1, 30240, 569744280, 1972495637280, 1600434039456630, 374736233227188672
OFFSET
0,2
CROSSREFS
Sequence in context: A218029 A323991 A109485 * A171263 A233731 A187376
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 09 2009
STATUS
approved