A146425 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1010-1111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 3, 7, 15, 27, 47, 145, 629, 2639, 10689, 40727, 200517, 1226295, 9011761, 67694903, 542738577, 4721537297, 50165476303, 597630948157

Offset

1,7

Links

Table of n, a(n) for n=1..24.

Example

Maximal 8 X 8 example
.0.0.0.1.0.1.0.0
.0.0.1.1.1.1.0.0
.0.1.0.0.0.0.1.1
.1.1.0.0.0.0.1.0
.0.1.0.0.0.0.1.1
.1.1.0.0.0.0.1.0
.0.0.1.1.1.1.0.0
.0.0.1.0.1.0.0.0

Crossrefs

Sequence in context: A097080 A274008 A146742 * A147595 A147127 A146726

Adjacent sequences: A146422 A146423 A146424 * A146426 A146427 A146428

Keyword

nonn

Author

R. H. Hardin

Status

approved