A146937 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1111-1111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 2, 3, 6, 9, 14, 23, 61, 135, 392, 922, 2676, 7151, 26809, 87678, 375597, 1374921, 6569486, 27726558, 157145315, 778948913, 5094691047, 28915328479, 216796412908

Offset

1,8

Links

Table of n, a(n) for n=1..30.

Example

Maximal 8 X 8 example
.0.0.1.1.1.1.0.0
.0.0.1.1.1.1.0.0
.1.1.0.0.0.0.1.1
.1.1.0.0.0.0.1.1
.1.1.0.0.0.0.1.1
.1.1.0.0.0.0.1.1
.0.0.1.1.1.1.0.0
.0.0.1.1.1.1.0.0

Crossrefs

Sequence in context: A018060 A115856 A147007 * A032231 A200273 A303664

Adjacent sequences: A146934 A146935 A146936 * A146938 A146939 A146940

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved