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A147271 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1000-1000-1111-0001 pattern in any orientation. 0
1, 1, 1, 1, 1, 3, 9, 23, 45, 169, 1061, 6743, 40273, 284761, 2852385, 36414365, 522818739, 8493813357, 169218922641 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.0.0.0.0

.0.0.0.0.0.0.0.0

.0.0.0.0.1.0.0.0

.0.0.0.0.1.1.1.1

.0.0.1.1.0.0.0.1

.0.0.0.1.0.0.0.1

.0.0.0.1.0.0.0.0

.0.0.0.1.1.1.0.0

CROSSREFS

Sequence in context: A029512 A210027 A018555 * A230119 A146693 A227259

Adjacent sequences:  A147268 A147269 A147270 * A147272 A147273 A147274

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified December 10 15:09 EST 2019. Contains 329896 sequences. (Running on oeis4.)