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A146277 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 110-111-111 pattern in any orientation. 0
1, 1, 1, 1, 1, 1, 3, 3, 5, 5, 9, 9, 21, 21, 93, 93, 381, 381, 1551, 1551, 7459, 7459, 56347, 56347, 473995, 473995, 4321181 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

Table of n, a(n) for n=1..27.

EXAMPLE

Maximal 8 X 8 example

.1.1.1.0.0.1.1.1

.1.1.1.0.0.1.1.1

.1.1.0.0.0.0.1.1

.0.0.0.0.0.0.0.0

.0.0.0.0.0.0.0.0

.1.1.0.0.0.0.1.1

.1.1.1.0.0.1.1.1

.1.1.1.0.0.1.1.1

CROSSREFS

Sequence in context: A146914 A146253 A147040 * A050822 A187494 A283843

Adjacent sequences:  A146274 A146275 A146276 * A146278 A146279 A146280

KEYWORD

nonn

AUTHOR

R. H. Hardin

STATUS

approved

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Last modified November 28 13:47 EST 2021. Contains 349413 sequences. (Running on oeis4.)