A147251 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 11100-00100-00111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 3, 5, 11, 17, 47, 101, 251, 493, 1875, 5405, 23441, 71481, 351927, 1342835, 7434603, 30903299, 201078705, 1028625049

Offset

1,9

Links

Table of n, a(n) for n=1..26.

Example

Maximal 9 X 9 example
.0.0.0.0.0.1.1.1.0
.0.0.0.0.0.1.0.0.1
.0.0.0.1.1.1.0.0.1
.0.0.1.0.0.0.1.1.1
.0.0.1.0.0.0.1.0.0
.1.1.1.0.0.0.1.0.0
.1.0.0.1.1.1.0.0.0
.1.0.0.1.0.0.0.0.0
.0.1.1.1.0.0.0.0.0

Crossrefs

Sequence in context: A019386 A283064 A154622 * A146473 A282961 A165446

Adjacent sequences: A147248 A147249 A147250 * A147252 A147253 A147254

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved