A156426 Number of 18 X 18 arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to n.

1, 168992, 2037627900, 3518648357632, 1392671800456580, 166774503916789696, 7527949573364777296

Offset

0,2

Links

Table of n, a(n) for n=0..6.

Crossrefs

Sequence in context: A140941 A186550 A151618 * A156427 A185474 A034211

Adjacent sequences: A156423 A156424 A156425 * A156427 A156428 A156429

Keyword

nonn

Author

R. H. Hardin, Feb 09 2009

Status

approved