A147337 - OEIS

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A147337

Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 01000-11100-00111-00010 pattern in any orientation.

1, 1, 1, 1, 1, 1, 9, 21, 61, 255, 1001, 4645, 25381, 168687, 1415389

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

OFFSET

1,7

LINKS

Table of n, a(n) for n=1..15.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.0.0.1.0

.0.0.0.0.0.0.1.1

.0.0.0.0.0.1.1.0

.0.0.1.0.1.1.0.0