A146680 - OEIS

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A146680

Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1100-0111-1100 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 9, 20, 33, 56, 137, 404, 1209, 4087, 15733, 60343, 254309, 1153606, 5642466, 31006709, 182836767, 1183007758, 8378875432, 64857203324

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

OFFSET

1,8

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.1.0.1.0

.1.1.0.0.1.1.1.0

.0.1.1.1.0.1.0.0

.1.1.0.0.0.1.0.0

.0.0.1.0.0.0.1.1

.0.0.1.0.1.1.1.0

.0.1.1.1.0.0.1.1

.0.1.0.1.0.0.0.0

CROSSREFS

Sequence in context: A059108 A028566 A147479 * A143704 A128153 A249044

Adjacent sequences: A146677 A146678 A146679 * A146681 A146682 A146683

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved