A146420 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1000-1111-1000 pattern in any orientation.

1, 1, 1, 1, 5, 13, 29, 109, 438, 2055, 12862, 88991, 791639, 8191225, 106776687, 1583975637, 29823226111, 639792465701

Offset

1,5

Links

Table of n, a(n) for n=1..18.

Example

Maximal 8 X 8 example
.0.1.0.1.1.1.0.0
.0.1.0.0.1.0.0.0
.0.1.0.0.1.0.0.0
.1.1.1.0.1.0.0.0
.0.0.0.1.0.1.1.1
.0.0.0.1.0.0.1.0
.0.0.0.1.0.0.1.0
.0.0.1.1.1.0.1.0

Crossrefs

Sequence in context: A268963 A147349 A147288 * A147492 A182069 A085555

Adjacent sequences: A146417 A146418 A146419 * A146421 A146422 A146423

Keyword

nonn

Author

R. H. Hardin

Status

approved