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A146227 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1100-1111 pattern in any orientation. 0
1, 1, 1, 1, 3, 13, 37, 183, 817, 5601, 59649, 681701, 9890411, 176577709, 3939621645, 118135623109, 4491780681983, 213414295100783, 12753739646336971, 960252990758480757, 92263548659475375193 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

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

EXAMPLE

Maximal 8 X 8 example

.0.0.0.1.1.0.0.0

.0.0.0.1.1.0.0.0

.0.0.0.0.1.0.0.0

.1.1.0.0.1.0.1.1

.1.1.1.1.0.0.1.1

.0.0.0.0.0.0.0.1

.0.0.0.1.1.0.0.1

.0.0.0.1.1.1.1.0

CROSSREFS

Sequence in context: A024535 A196235 A120479 * A019007 A147554 A076800

Adjacent sequences:  A146224 A146225 A146226 * A146228 A146229 A146230

KEYWORD

nonn

AUTHOR

R. H. Hardin

STATUS

approved

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Last modified December 2 05:01 EST 2021. Contains 349437 sequences. (Running on oeis4.)