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A147273 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1000-1000-1111-0001 pattern in any orientation. 0
1, 1, 1, 1, 1, 1, 1, 1, 21, 41, 79, 171, 645, 1743, 5843, 17953, 98853, 402491, 2708743, 12396159 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

Maximal 9 X 9 example

.1.0.0.0.0.0.1.1.1

.1.0.0.0.0.0.1.0.0

.1.1.1.1.0.0.1.0.0

.0.0.0.1.0.1.1.0.0

.0.0.0.0.0.0.0.0.0

.0.0.1.1.0.1.0.0.0

.0.0.1.0.0.1.1.1.1

.0.0.1.0.0.0.0.0.1

.1.1.1.0.0.0.0.0.1

CROSSREFS

Sequence in context: A215145 A154576 A173960 * A195034 A067344 A053428

Adjacent sequences:  A147270 A147271 A147272 * A147274 A147275 A147276

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified November 17 16:08 EST 2019. Contains 329241 sequences. (Running on oeis4.)