A146908 - OEIS

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A146908

Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 0010-1110-0111-0100 pattern in any orientation.

0

1, 1, 1, 3, 1, 3, 5, 21, 49, 187, 409, 2325, 6489, 55121, 197983, 2161765, 11768363, 152495079, 1086067425, 18675930957, 164918184657, 3873609933855

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

OFFSET

1,4

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

Maximal 8 X 8 example

.0.0.1.0.0.0.1.0

.1.1.1.0.1.1.1.0

.0.1.1.1.0.1.1.1

.0.1.0.0.0.1.0.0

.0.0.1.0.0.0.1.0

.1.1.1.0.1.1.1.0

.0.1.1.1.0.1.1.1

.0.1.0.0.0.1.0.0

CROSSREFS

Sequence in context: A279697 A133179 A282221 * A279249 A281893 A049324

Adjacent sequences: A146905 A146906 A146907 * A146909 A146910 A146911

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved