A147181 - OEIS

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A147181

Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1000-1111-0101 pattern in any orientation.

1, 1, 1, 1, 1, 5, 17, 37, 129, 675, 4545, 33673, 284663, 3050875, 41150087, 686710451, 13852947253, 339116701643, 10235218350849, 379099740909573

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

OFFSET

1,6

LINKS

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

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.0.0.0.0

.0.0.0.0.1.0.0.0

.0.0.0.0.1.1.1.1

.0.0.1.1.0.1.0.1

.0.0.0.1.1.0.0.0

.0.0.0.1.0.0.0.0

.0.0.0.1.1.0.0.0

CROSSREFS

Sequence in context: A147219 A146280 A282511 * A146850 A146428 A146235

Adjacent sequences: A147178 A147179 A147180 * A147182 A147183 A147184

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved