A156474 Number of n X n arrays of squares of integers, symmetric under 90 degree rotation, with all rows summing to 20.

4, 7, 78, 660, 19896, 352350, 29182380, 1150637340, 215977376730

Offset

4,1

Links

Table of n, a(n) for n=4..12.

Crossrefs

Sequence in context: A135790 A253202 A368271 * A136276 A072954 A322723

Adjacent sequences: A156471 A156472 A156473 * A156475 A156476 A156477

Keyword

nonn

Author

R. H. Hardin Feb 09 2009

Status

approved