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A147136 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 1000-1001-1111 pattern in any orientation. 0
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 13, 13, 31, 31, 81, 81, 343 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,13

LINKS

Table of n, a(n) for n=1..21.

CROSSREFS

Sequence in context: A147032 A146261 A146176 * A146844 A146193 A146727

Adjacent sequences: A147133 A147134 A147135 * A147137 A147138 A147139

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified December 4 16:41 EST 2022. Contains 358563 sequences. (Running on oeis4.)