A147257 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 0001-1101-0111 pattern in any orientation.

1, 1, 1, 1, 1, 5, 17, 39, 137, 661, 3965, 30475, 261877, 2593597, 32463645, 507974205, 9631596681, 224195557727, 6341197277447, 216685113312141, 8987183183859385

Offset

1,6

Links

Table of n, a(n) for n=1..21.

Example

Maximal 8 X 8 example
.0.0.0.1.1.1.0.0
.0.0.0.1.0.0.1.0
.0.0.0.1.1.0.1.1
.1.1.1.0.1.0.0.1
.1.0.1.1.0.1.1.1
.1.0.0.0.1.0.0.0
.0.1.1.0.1.0.0.0
.0.0.1.1.1.0.0.0

Crossrefs

Sequence in context: A250413 A163686 A147165 * A146645 A146717 A147467

Adjacent sequences: A147254 A147255 A147256 * A147258 A147259 A147260

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved