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A146854 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1100-1111-0001 pattern in any orientation. 0
1, 1, 1, 1, 5, 21, 55, 223, 1323, 7243, 56001, 498505, 5857355, 89335203, 1598206021, 35814813801 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..16.

EXAMPLE

Maximal 8 X 8 example

.0.1.1.0.0.1.1.0

.0.0.1.0.0.0.1.0

.0.0.1.1.0.0.1.1

.0.0.1.1.0.0.1.1

.1.1.0.0.1.1.0.0

.1.1.0.0.1.1.0.0

.0.1.0.0.0.1.0.0

.0.1.1.0.0.1.1.0

CROSSREFS

Sequence in context: A201440 A096942 A122244 * A299120 A033275 A166464

Adjacent sequences: A146851 A146852 A146853 * A146855 A146856 A146857

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified February 2 16:10 EST 2023. Contains 360023 sequences. (Running on oeis4.)