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A146221 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 101-111-010 pattern in any orientation. 0
1, 1, 1, 1, 1, 1, 2, 1, 4, 1, 8, 3, 27, 9, 104, 20, 436, 63, 2340, 272, 15459, 1557, 131790, 10412, 1346197, 77761, 16419748, 729051, 247609178, 8641753 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

Maximal 9 X 9 example

.0.0.0.0.0.0.0.0.0

.0.0.0.1.0.1.0.0.0

.0.0.0.1.1.1.0.0.0

.0.1.1.0.1.0.1.1.0

.0.0.1.1.0.1.1.0.0

.0.1.1.0.1.0.1.1.0

.0.0.0.1.1.1.0.0.0

.0.0.0.1.0.1.0.0.0

.0.0.0.0.0.0.0.0.0

CROSSREFS

Sequence in context: A147441 A146269 A146679 * A147457 A107061 A112481

Adjacent sequences:  A146218 A146219 A146220 * A146222 A146223 A146224

KEYWORD

nonn

AUTHOR

R. H. Hardin

STATUS

approved

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Last modified January 16 19:48 EST 2022. Contains 350376 sequences. (Running on oeis4.)