A156439 Number of n X n arrays of squares of integers, symmetric under 90 degree rotation, with all rows summing to 5.

2, 3, 0, 0, 480, 2400, 0, 0, 7574400, 66083040, 0, 0, 896812758240, 10058239033920, 0, 0, 374736233227188672, 5125335197750964000, 0, 0

Offset

4,1

Links

Table of n, a(n) for n=4..23.

Crossrefs

Sequence in context: A240658 A342315 A063890 * A087734 A073644 A123343

Adjacent sequences: A156436 A156437 A156438 * A156440 A156441 A156442

Keyword

nonn

Author

R. H. Hardin Feb 09 2009

Status

approved