A145793 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only either four adjacent vertically or four adjacent horizontally.

1, 1, 1, 1, 1, 2, 3, 5, 8, 17, 40, 108, 294, 944, 3040, 12114, 49757, 243775, 1210271, 7153531, 43484383, 316861269, 2366046579, 21108349931, 192219307524, 2092034177623, 23326966046445, 311290850669433, 4251413939111348

Offset

1,6

Links

Table of n, a(n) for n=1..29.

Crossrefs

Sequence in context: A123612 A077177 A303874 * A113879 A205303 A025071

Adjacent sequences: A145790 A145791 A145792 * A145794 A145795 A145796

Keyword

nonn

Author

R. H. Hardin, Oct 19 2008

Status

approved