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A146420 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1000-1111-1000 pattern in any orientation. 0
1, 1, 1, 1, 5, 13, 29, 109, 438, 2055, 12862, 88991, 791639, 8191225, 106776687, 1583975637, 29823226111, 639792465701 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

Maximal 8 X 8 example

.0.1.0.1.1.1.0.0

.0.1.0.0.1.0.0.0

.0.1.0.0.1.0.0.0

.1.1.1.0.1.0.0.0

.0.0.0.1.0.1.1.1

.0.0.0.1.0.0.1.0

.0.0.0.1.0.0.1.0

.0.0.1.1.1.0.1.0

CROSSREFS

Sequence in context: A268963 A147349 A147288 * A147492 A182069 A085555

Adjacent sequences:  A146417 A146418 A146419 * A146421 A146422 A146423

KEYWORD

nonn

AUTHOR

R. H. Hardin

STATUS

approved

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Last modified September 28 06:57 EDT 2021. Contains 347703 sequences. (Running on oeis4.)