A146401 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1111-0010 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 3, 9, 19, 33, 77, 239, 919, 3879, 17353, 75579, 398897, 2332505, 16656293, 126029691, 1117371931, 10274166583

Offset

1,8

Links

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

Example

Maximal 8 X 8 example
.0.0.0.0.0.1.0.0
.0.0.1.1.1.1.0.0
.0.1.0.1.0.0.1.1
.0.1.1.0.0.0.1.0
.0.1.0.0.0.1.1.0
.1.1.0.0.1.0.1.0
.0.0.1.1.1.1.0.0
.0.0.1.0.0.0.0.0

Crossrefs

Sequence in context: A146670 A146409 A147111 * A146465 A147119 A146184

Adjacent sequences: A146398 A146399 A146400 * A146402 A146403 A146404

Keyword

nonn

Author

R. H. Hardin

Status

approved