A147394 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1000-1000-1111-0001-0001 pattern in any orientation.

1, 1, 1, 1, 1, 1, 3, 7, 15, 27, 67, 281, 1263, 5491, 23639, 128337, 894617, 7261755, 63564439, 605898697, 6745478781, 88749999709, 1352715152779

Offset

1,7

Links

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

Example

Maximal 8 X 8 example
.0.0.0.0.0.0.0.0
.0.0.0.0.1.0.0.0
.0.0.0.0.1.0.0.0
.0.0.0.0.1.1.1.1
.0.1.1.1.0.0.0.1
.0.0.0.1.0.0.0.1
.0.0.0.1.0.0.0.0
.0.0.0.1.1.1.0.0

Crossrefs

Sequence in context: A143701 A147638 A343440 * A350370 A103021 A025587

Adjacent sequences: A147391 A147392 A147393 * A147395 A147396 A147397

Keyword

nonn

Author

R. H. Hardin

Status

approved