A146609 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A146609

Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1000-1111-0001 pattern in any orientation.

1, 1, 1, 1, 5, 13, 31, 93, 435, 2055, 12617, 84101, 749259, 7832803, 101765203, 1516307327, 27862176903, 604272411455

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

OFFSET

1,5

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.1.0.0.1.1

.1.1.1.1.0.0.1.0

.1.0.0.0.0.0.1.0

.0.0.0.0.0.1.1.0

.0.1.1.0.0.0.0.0

.0.1.0.0.0.0.0.1

.0.1.0.0.1.1.1.1

.1.1.0.0.1.0.0.0

CROSSREFS

Sequence in context: A097969 A082280 A007708 * A121129 A051402 A147022

Adjacent sequences: A146606 A146607 A146608 * A146610 A146611 A146612

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved