A146428 - OEIS

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A146428

Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1010-1111 pattern in any orientation.

1, 1, 1, 5, 17, 37, 137, 887, 6015, 58025, 613977, 8063295, 140732661, 3250417071

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

OFFSET

1,4

LINKS

Table of n, a(n) for n=1..14.

EXAMPLE

Maximal 8 X 8 example

.1.1.0.0.1.0.1.1

.0.1.0.0.1.1.0.1

.1.1.0.0.1.0.1.1

.0.1.0.0.1.1.0.1

.1.0.1.1.0.0.1.0

.1.1.0.1.0.0.1.1

.1.0.1.1.0.0.1.0

.1.1.0.1.0.0.1.1

CROSSREFS

Sequence in context: A282511 A147181 A146850 * A146235 A087728 A072332

Adjacent sequences: A146425 A146426 A146427 * A146429 A146430 A146431

KEYWORD

nonn

AUTHOR

R. H. Hardin

STATUS

approved