A146231 - OEIS

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A146231

Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1100-1111 pattern in any orientation.

1, 1, 1, 5, 17, 35, 163, 959, 6943, 61513, 740733, 9820359, 193942865, 4360418313, 137513801459

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

OFFSET

1,4

LINKS

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

EXAMPLE

Maximal 8 X 8 example

.1.1.0.0.1.1.1.1

.1.1.1.1.0.0.1.1

.0.0.0.0.0.0.0.0

.1.1.0.0.1.1.1.1

.1.1.1.1.0.0.1.1

.0.0.0.0.0.0.0.0

.1.1.0.0.1.1.1.1

.1.1.1.1.0.0.1.1

CROSSREFS

Sequence in context: A297520 A026394 A004538 * A186029 A083048 A123669

Adjacent sequences: A146228 A146229 A146230 * A146232 A146233 A146234

KEYWORD

nonn

AUTHOR

R. H. Hardin

STATUS

approved