A146041 - 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

A146041

Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 2X4 tee 1,1 1,2 1,3 2,3 1,4 in any orientation.

1, 1, 1, 1, 5, 21, 83, 385, 2131, 24025, 318135, 5078109, 98561015, 2403657061, 86079554793, 4029871316637, 240018399697859, 18147620162041911, 1762019890516576641, 229246937643264356069, 39291648711744977550585

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

OFFSET

1,5

LINKS

Table of n, a(n) for n=1..21.

EXAMPLE

Maximal 8 X 8 example

.0.1.1.1.1.0.0.0

.1.0.1.0.0.0.0.0

.1.1.0.1.1.1.1.0

.1.0.1.0.1.0.0.1

.1.0.1.1.0.0.0.1

.0.0.1.0.0.0.1.1

.0.0.1.0.0.1.0.1

.0.0.0.1.1.1.1.0

CROSSREFS

Sequence in context: A026017 A132310 A083319 * A146585 A351363 A215008

Adjacent sequences: A146038 A146039 A146040 * A146042 A146043 A146044

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 26 2008

STATUS

approved