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A147040 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 0100-0100-1111-0100 pattern in any orientation. 0
1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 5, 5, 9, 9, 21, 21, 69, 69, 305, 305, 1333, 1333, 6087, 6087, 37147, 37147, 280959, 280959 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

LINKS

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

EXAMPLE

Maximal 9 X 9 example

.0.0.1.0.0.0.1.0.0

.0.0.1.0.0.0.1.0.0

.1.1.1.1.0.1.1.1.1

.0.0.1.0.0.0.1.0.0

.0.0.0.0.0.0.0.0.0

.0.0.1.0.0.0.1.0.0

.1.1.1.1.0.1.1.1.1

.0.0.1.0.0.0.1.0.0

.0.0.1.0.0.0.1.0.0

CROSSREFS

Sequence in context: A147472 A146914 A146253 * A146277 A050822 A187494

Adjacent sequences:  A147037 A147038 A147039 * A147041 A147042 A147043

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified December 8 01:25 EST 2021. Contains 349590 sequences. (Running on oeis4.)