A146820 - OEIS

A146820

Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 1000-1110-0111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 9, 9, 23, 23, 59, 59, 317, 317, 2143, 2143, 14651

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OFFSET

1,11

LINKS

Table of n, a(n) for n=1..23.

EXAMPLE

Maximal 11 X 11 example

.0.0.1.1.0.0.0.1.1.0.0

.0.0.0.1.1.0.1.1.0.0.0

.1.0.0.1.1.0.1.1.0.0.1

.1.1.1.0.1.0.1.0.1.1.1

.0.1.1.1.0.0.0.1.1.1.0

.0.0.0.0.0.0.0.0.0.0.0

.0.1.1.1.0.0.0.1.1.1.0

.1.1.1.0.1.0.1.0.1.1.1

.1.0.0.1.1.0.1.1.0.0.1

.0.0.0.1.1.0.1.1.0.0.0

.0.0.1.1.0.0.0.1.1.0.0

CROSSREFS

Sequence in context: A146442 A147128 A147214 * A146663 A146394 A147510

Adjacent sequences: A146817 A146818 A146819 * A146821 A146822 A146823

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved