A147455 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 11000-01111-11000 pattern in any orientation.

1, 1, 1, 1, 1, 1, 3, 9, 19, 53, 174, 577, 2638, 14887, 91688, 621981, 4953292, 45339549, 483440905, 6106017477, 89757755470, 1517774827657, 29582954137388

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
.0.0.0.0.0.0.1.1
.0.0.0.1.1.1.1.0
.0.0.1.0.0.0.1.1
.0.0.1.0.0.0.0.0
.0.0.1.0.0.0.0.0
.0.1.1.1.0.0.0.0
.0.1.0.1.0.0.0.0

Crossrefs

Sequence in context: A147477 A146677 A077442 * A146429 A297390 A018316

Adjacent sequences: A147452 A147453 A147454 * A147456 A147457 A147458

Keyword

nonn

Author

R. H. Hardin

Status

approved