A141445 Number of n X n integer matrices, symmetric under 180 degree rotation, with adjacent elements differing by no more than 1, counting matrices differing by a constant only once.

1, 3, 45, 597, 42787, 2695803, 923529659, 278451121903, 457744547778601, 663065487350675885

Offset

1,2

Links

Table of n, a(n) for n=1..10.

Crossrefs

Sequence in context: A060242 A271236 A270064 * A076140 A131568 A287031

Adjacent sequences: A141442 A141443 A141444 * A141446 A141447 A141448

Keyword

nonn

Author

R. H. Hardin, Aug 06 2008

Status

approved