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A146018 Number of n X n binary arrays symmetric about main diagonal 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, 3, 13, 41, 219, 1033, 8217, 92671, 1241193, 21102313, 438374597, 11919134635, 429471270295, 20089457592037, 1200700834920789, 91306423605321353, 8917989878582336861 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.1.0.0.0

.0.0.0.0.1.0.0.1

.0.0.0.0.1.0.0.1

.0.0.0.0.1.1.0.1

.1.1.1.1.0.0.1.1

.0.0.0.1.0.0.0.0

.0.0.0.0.1.0.0.0

.0.1.1.1.1.0.0.0

CROSSREFS

Sequence in context: A234387 A173867 A121162 * A145946 A109224 A106050

Adjacent sequences:  A146015 A146016 A146017 * A146019 A146020 A146021

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 26 2008

STATUS

approved

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Last modified October 19 14:45 EDT 2021. Contains 348090 sequences. (Running on oeis4.)