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A147031 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 0100-0100-1111-0010 pattern in any orientation. 0
1, 1, 1, 1, 1, 1, 1, 1, 5, 13, 25, 43, 89, 283, 1197, 5015, 19569, 70793, 320835, 1805563, 12416113, 87073927 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

Maximal 9 X 9 example

.0.0.0.0.1.0.0.0.0

.0.0.1.1.1.0.0.0.0

.0.1.0.0.1.1.0.0.0

.0.1.0.0.1.0.1.0.0

.1.1.1.1.0.1.1.1.1

.0.0.1.0.1.0.0.1.0

.0.0.0.1.1.0.0.1.0

.0.0.0.0.1.1.1.0.0

.0.0.0.0.1.0.0.0.0

CROSSREFS

Sequence in context: A240001 A301685 A102724 * A147220 A269713 A196069

Adjacent sequences:  A147028 A147029 A147030 * A147032 A147033 A147034

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified January 24 04:47 EST 2022. Contains 350534 sequences. (Running on oeis4.)