A147135 - OEIS

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A147135

Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1001-1111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 3, 9, 19, 33, 59, 157, 473, 1581, 5917, 23197, 94123, 435079, 2125669

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

OFFSET

1,9

LINKS

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

EXAMPLE

Maximal 9 X 9 example

.0.0.0.1.1.1.1.0.0

.0.0.0.1.0.0.1.0.0

.0.0.0.1.0.0.0.1.1

.1.1.1.0.0.0.0.0.1

.1.0.0.0.0.0.0.0.1

.1.0.0.0.0.0.1.1.1

.1.1.0.0.0.1.0.0.0

.0.0.1.0.0.1.0.0.0

.0.0.1.1.1.1.0.0.0

CROSSREFS

Sequence in context: A049749 A147055 A146638 * A146843 A146630 A146710

Adjacent sequences: A147132 A147133 A147134 * A147136 A147137 A147138

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved