A156428 Number of 20 X 20 arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to n.

1, 921184, 52745205240, 367381371180384, 514918876680042334, 195842622547532763968

Offset

0,2

Links

Table of n, a(n) for n=0..5.

Crossrefs

Sequence in context: A185532 A360907 A321323 * A251954 A098208 A251172

Adjacent sequences: A156425 A156426 A156427 * A156429 A156430 A156431

Keyword

nonn

Author

R. H. Hardin, Feb 09 2009

Status

approved