A147252 - OEIS

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A147252

Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 11100-00100-00111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 7, 7, 15, 15, 31, 31, 125, 125, 537, 537, 2497, 2497, 11379

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

OFFSET

1,13

LINKS

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

EXAMPLE

Maximal 13 X 13 example

.0.0.0.1.0.0.0.0.0.1.0.0.0

.0.0.0.1.1.1.0.1.1.1.0.0.0

.1.1.1.0.0.1.0.1.0.0.1.1.1

.0.0.1.0.0.1.0.1.0.0.1.0.0

.0.0.1.1.1.0.0.0.1.1.1.0.0

.0.0.0.0.0.0.0.0.0.0.0.0.0

.0.0.1.1.1.0.0.0.1.1.1.0.0

.0.0.1.0.0.1.0.1.0.0.1.0.0

.1.1.1.0.0.1.0.1.0.0.1.1.1

.0.0.0.1.1.1.0.1.1.1.0.0.0

.0.0.0.1.0.0.0.0.0.1.0.0.0

CROSSREFS

Sequence in context: A147402 A052551 A147096 * A147104 A147381 A146035

Adjacent sequences: A147249 A147250 A147251 * A147253 A147254 A147255

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved