A146141 - OEIS

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A146141

Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 5-point barb 1,1 1,2 2,2 2,3 3,2 in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 7, 21, 21, 61, 61, 403, 403, 3415, 3415, 36395, 36395, 473261, 473261, 8291363, 8291363, 204964495, 204964495

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,11

LINKS

Table of n, a(n) for n=1..28.

EXAMPLE

Maximal 11 X 11 example

.0.0.0.1.0.0.0.1.0.0.0

.0.0.1.1.0.0.0.1.1.0.0

.0.1.0.1.1.0.1.1.0.1.0

.1.1.1.0.0.0.0.0.1.1.1

.0.0.1.0.0.0.0.0.1.0.0

.0.0.0.0.0.0.0.0.0.0.0

.0.0.1.0.0.0.0.0.1.0.0

.1.1.1.0.0.0.0.0.1.1.1

.0.1.0.1.1.0.1.1.0.1.0

.0.0.1.1.0.0.0.1.1.0.0

.0.0.0.1.0.0.0.1.0.0.0

CROSSREFS

Sequence in context: A146402 A146410 A146466 * A062368 A283067 A284185

Adjacent sequences: A146138 A146139 A146140 * A146142 A146143 A146144

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 27 2008

STATUS

approved