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A146019 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 2X4 el 1,1 1,2 1,3 1,4 2,4 with any orientation. 0
1, 1, 1, 1, 1, 1, 3, 7, 15, 29, 61, 211, 895, 3955, 16593, 80999, 462679, 3239573, 25414255, 222500583, 2101470837, 23313975471, 290908388247, 4246548210105, 68354920234083 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.0.1.0.0

.0.0.1.1.1.1.0.0

.0.1.0.0.0.0.1.1

.0.1.0.0.0.0.1.0

.0.1.0.0.0.0.1.0

.1.1.0.0.0.0.1.0

.0.0.1.1.1.1.0.0

.0.0.1.0.0.0.0.0

CROSSREFS

Sequence in context: A284022 A327554 A120538 * A284421 A283864 A283606

Adjacent sequences:  A146016 A146017 A146018 * A146020 A146021 A146022

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 26 2008

STATUS

approved

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Last modified October 22 05:36 EDT 2021. Contains 348160 sequences. (Running on oeis4.)