login

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”).

A147371
Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 0111-1100-0111 pattern in any orientation.
0
1, 1, 1, 1, 1, 3, 9, 19, 42, 149, 642, 3217, 16918, 103595, 764774, 6743975, 68369223, 809162389, 11357687762, 186710566988, 3547308633892, 78610913689329, 2049663760103557, 62999437730030008
OFFSET
1,6
EXAMPLE
Maximal 8 X 8 example
.0.0.0.0.0.0.0.0
.0.0.0.0.1.1.1.0
.0.0.0.0.0.0.1.1
.0.0.0.0.1.1.1.0
.0.1.0.1.0.0.0.0
.0.1.0.1.0.0.0.0
.0.1.1.1.0.0.0.0
.0.0.1.0.0.0.0.0
CROSSREFS
Sequence in context: A373309 A153084 A285927 * A075188 A051894 A146393
KEYWORD
nonn
AUTHOR
STATUS
approved