A146173 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 110-100-111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 9, 9, 33, 33, 89, 89, 853, 853, 34557, 34557, 906369, 906369, 18920177, 18920177, 1254520087, 1254520087, 193995577775, 193995577775

Offset

1,7

Links

Table of n, a(n) for n=1..24.

Example

Maximal 8 X 8 example
.1.0.0.0.0.0.0.1
.1.0.1.0.0.1.0.1
.1.1.1.0.0.1.1.1
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.1.1.1.0.0.1.1.1
.1.0.1.0.0.1.0.1
.1.0.0.0.0.0.0.1

Crossrefs

Sequence in context: A146825 A147029 A146258 * A146190 A147125 A147109

Adjacent sequences: A146170 A146171 A146172 * A146174 A146175 A146176

Keyword

nonn

Author

R. H. Hardin, Oct 27 2008

Status

approved