A140424 Number of n X n symmetric binary matrices with every 1 adjacent to some 0 horizontally or vertically.

1, 5, 33, 413, 10601, 528337, 51239609, 9724918961, 3609411455769, 2618162731691205, 3712251419364788297, 10289169690673968652093, 55746140612201223800718641, 590390724169460591054420145025

Offset

1,2

Links

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

Crossrefs

Sequence in context: A087618 A322178 A134152 * A295090 A350876 A268296

Adjacent sequences: A140421 A140422 A140423 * A140425 A140426 A140427

Keyword

nonn

Author

R. H. Hardin, Jun 18 2008

Status

approved