A146598 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1000-1111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 3, 7, 15, 31, 71, 203, 581, 2061, 8089, 33693, 163089, 819567, 4807311, 30022515, 215155907, 1673895429

Offset

1,8

Links

Table of n, a(n) for n=1..23.

Example

Maximal 8 X 8 example
.0.0.0.1.1.1.1.0
.0.0.0.1.0.0.0.1
.0.0.0.1.0.0.0.1
.1.1.1.0.0.0.0.1
.1.0.0.0.0.1.1.1
.1.0.0.0.1.0.0.0
.1.0.0.0.1.0.0.0
.0.1.1.1.1.0.0.0

Crossrefs

Sequence in context: A146811 A147235 A024876 * A147094 A326518 A147285

Adjacent sequences: A146595 A146596 A146597 * A146599 A146600 A146601

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved