A141444 Number of n X n integer matrices, symmetric under 90-degree rotation, with adjacent elements differing by no more than 1, counting matrices differing by a constant only once.

1, 1, 9, 17, 309, 1265, 48927, 435807, 36527739, 709448287, 129684847323, 5504589599263, 2200548059561679, 204460755826652731

Offset

1,3

Links

Table of n, a(n) for n=1..14.

Crossrefs

Sequence in context: A110360 A371031 A123836 * A061748 A159510 A191675

Adjacent sequences: A141441 A141442 A141443 * A141445 A141446 A141447

Keyword

nonn

Author

R. H. Hardin, Aug 06 2008

Status

approved