A146606 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1111-0001 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 3, 7, 13, 23, 55, 135, 381, 1155, 4259, 15095, 63361, 271287, 1364019, 7046127, 42849769, 267209541, 1961120087, 14636956303, 129172123843, 1159685046407, 12305875469689

Offset

1,9

Links

Table of n, a(n) for n=1..29.

Example

Maximal 9 X 9 example
.0.0.0.0.0.0.1.0.0
.0.0.0.1.1.1.1.0.0
.0.0.0.1.0.0.0.1.1
.0.1.1.0.0.0.0.1.0
.0.1.0.0.0.0.0.1.0
.0.1.0.0.0.0.1.1.0
.1.1.0.0.0.1.0.0.0
.0.0.1.1.1.1.0.0.0
.0.0.1.0.0.0.0.0.0

Crossrefs

Sequence in context: A297953 A084898 A147380 * A101302 A102948 A232533

Adjacent sequences: A146603 A146604 A146605 * A146607 A146608 A146609

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved