A146275 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 110-111-111 pattern in any orientation.

1, 1, 3, 5, 9, 21, 93, 381, 1551, 7459, 56347, 473995, 4321181, 46467441, 656149111, 10982021937, 211884167843, 4855692779387, 137589956676037, 4668303218338689, 186691871576131219, 8904751201199219747, 514295038831216408667

Offset

1,3

Links

Table of n, a(n) for n=1..23.

Example

Maximal 8 X 8 example
.0.1.1.0.0.1.1.1
.1.1.1.0.0.1.1.1
.1.1.1.0.0.0.1.1
.0.0.0.1.1.1.0.0
.0.0.0.1.1.1.0.0
.1.1.0.1.1.0.1.1
.1.1.1.0.0.1.1.1
.1.1.1.0.0.1.1.1

Crossrefs

Sequence in context: A328525 A125517 A147038 * A089636 A241398 A262483

Adjacent sequences: A146272 A146273 A146274 * A146276 A146277 A146278

Keyword

nonn

Author

R. H. Hardin

Status

approved