A146221 - OEIS

A146221

Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 101-111-010 pattern in any orientation.

1, 1, 1, 1, 1, 1, 2, 1, 4, 1, 8, 3, 27, 9, 104, 20, 436, 63, 2340, 272, 15459, 1557, 131790, 10412, 1346197, 77761, 16419748, 729051, 247609178, 8641753

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,7

LINKS

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

EXAMPLE

Maximal 9 X 9 example

.0.0.0.0.0.0.0.0.0

.0.0.0.1.0.1.0.0.0

.0.0.0.1.1.1.0.0.0

.0.1.1.0.1.0.1.1.0

.0.0.1.1.0.1.1.0.0