A146875 - OEIS

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A146875

Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1110-0100-0111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 5, 13, 25, 41, 109, 333, 897, 2841, 13365, 66133, 320121, 1501457, 8213389, 51555309

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

OFFSET

1,9

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

Maximal 9 X 9 example

.0.0.0.0.1.1.1.0.0

.0.0.0.0.0.1.0.0.0

.0.0.0.1.1.1.0.0.1

.0.0.1.0.0.0.1.1.1

.1.0.1.0.0.0.1.0.1

.1.1.1.0.0.0.1.0.0

.1.0.0.1.1.1.0.0.0

.0.0.0.1.0.0.0.0.0

.0.0.1.1.1.0.0.0.0

CROSSREFS

Sequence in context: A146590 A098483 A147205 * A241233 A064276 A240001

Adjacent sequences: A146872 A146873 A146874 * A146876 A146877 A146878

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved