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

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