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A146661 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1100-0111-0001 pattern in any orientation. 0
1, 1, 1, 1, 3, 9, 23, 67, 379, 2563, 18843, 171357, 2142397, 34085501, 656314291, 15909337201, 492190457043, 19216875516479, 939930272232161 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

Maximal 8 X 8 example

.0.0.1.1.0.0.0.0

.0.0.0.1.0.0.0.1

.1.0.0.1.1.0.1.1

.1.1.1.0.1.0.1.0

.0.0.1.1.0.1.1.0

.0.0.0.0.1.0.0.0

.0.0.1.1.1.0.0.0

.0.1.1.0.0.0.0.0

CROSSREFS

Sequence in context: A018044 A047045 A164949 * A004666 A196488 A108488

Adjacent sequences:  A146658 A146659 A146660 * A146662 A146663 A146664

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified June 29 18:25 EDT 2022. Contains 354913 sequences. (Running on oeis4.)