A146431 - OEIS

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A146431

Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 101-111-101 pattern in any orientation.

1, 1, 3, 1, 3, 1, 9, 3, 31, 9, 301, 19, 1647, 53, 11872, 531, 136892, 5709, 3186390, 48307, 72335276, 490649, 1826857009, 11283333, 67665636761, 359196547, 4149252095689, 11541091447, 314296409403995, 440660012263

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

OFFSET

1,3

LINKS

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

EXAMPLE

Maximal 8 X 8 example

.1.0.1.0.0.1.0.1

.1.1.1.0.0.1.1.1

.1.0.1.0.0.1.0.1

.0.0.0.0.0.0.0.0

.1.0.1.0.0.1.0.1