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A146639 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 1010-1111-0100 pattern in any orientation. 0
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 7, 21, 21, 49, 49, 223, 223, 1043, 1043, 7899 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,13

LINKS

Table of n, a(n) for n=1..23.

EXAMPLE

Maximal 13 X 13 example

.0.0.0.1.0.1.0.1.0.1.0.0.0

.0.0.1.1.1.1.0.1.1.1.1.0.0

.0.1.0.0.1.0.0.0.1.0.0.1.0

.1.1.0.0.0.0.0.0.0.0.0.1.1

.0.1.1.0.0.0.0.0.0.0.1.1.0

.1.1.0.0.0.0.0.0.0.0.0.1.1

.0.0.0.0.0.0.0.0.0.0.0.0.0

.1.1.0.0.0.0.0.0.0.0.0.1.1

.0.1.1.0.0.0.0.0.0.0.1.1.0

.1.1.0.0.0.0.0.0.0.0.0.1.1

.0.1.0.0.1.0.0.0.1.0.0.1.0

.0.0.1.1.1.1.0.1.1.1.1.0.0

.0.0.0.1.0.1.0.1.0.1.0.0.0

CROSSREFS

Sequence in context: A147056 A146631 A146671 * A146703 A146615 A146735

Adjacent sequences:  A146636 A146637 A146638 * A146640 A146641 A146642

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

EXTENSIONS

Example repaired. - R. H. Hardin, Nov 05 2008

STATUS

approved

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Last modified May 18 00:59 EDT 2022. Contains 353779 sequences. (Running on oeis4.)