A140196 Number of symmetric binary n X n matrices with every 1 adjacent horizontally (and vertically) to some 0.

1, 5, 21, 175, 2665, 69147, 3183841, 259010439, 36989095651, 9310549716061, 4127913626714981, 3221885485823007739, 4428893445413111685241, 10721218357954583752212691, 45702135675375111739043639093

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Crossrefs

Sequence in context: A318966 A117067 A123334 * A027160 A195963 A119686

Adjacent sequences: A140193 A140194 A140195 * A140197 A140198 A140199

Keyword

nonn

Author

R. H. Hardin, Jun 15 2008

Status

approved