A146380 - OEIS

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A146380

Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 0100-1111-0100 pattern in any orientation.

1, 1, 1, 1, 1, 13, 27, 135, 527, 2581, 17899, 176183, 1596080, 23232289, 321756402, 6986541337, 150961652645, 4812704574943, 154830665386988

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

OFFSET

1,6

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.0.1.0.0

.0.0.0.0.1.1.1.1

.0.1.0.0.0.1.0.0

.1.1.1.1.0.0.1.0

.0.1.0.0.1.1.1.1

.0.0.1.0.0.0.1.0

.1.1.1.1.0.0.0.0

.0.0.1.0.0.0.0.0

CROSSREFS

Sequence in context: A098266 A041332 A041334 * A146372 A018946 A042397

Adjacent sequences: A146377 A146378 A146379 * A146381 A146382 A146383

KEYWORD

nonn

AUTHOR

R. H. Hardin

STATUS

approved