A146271 - OEIS

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A146271

Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 110-111-110 pattern in any orientation.

0

1, 1, 1, 1, 5, 17, 56, 271, 962, 4903, 45104, 358857, 4309512, 55284185, 919547239, 17250892544, 432277811298, 11665546694793, 439099597024204

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

OFFSET

1,5

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.0.1.1.1

.0.0.0.0.0.1.1.1

.0.1.1.1.0.0.1.0

.0.1.1.1.0.1.0.0

.0.0.1.0.1.1.1.0

.0.1.0.0.1.1.1.0

.1.1.1.0.0.0.0.0

.1.1.1.0.0.0.0.0

CROSSREFS

Sequence in context: A191645 A146240 A112410 * A145371 A347750 A112044

Adjacent sequences: A146268 A146269 A146270 * A146272 A146273 A146274

KEYWORD

nonn

AUTHOR

STATUS

approved