A191477 Number of n X n symmetric binary matrices with each 1 adjacent to no more than 1 king-move neighboring 1

2, 5, 15, 92, 716, 8595, 156804, 4204649, 170016558, 10240395108, 922770471915, 124331209274267, 25029189338772296, 7533759271342997075, 3389438730483714015640, 2279436096066483952197622

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..24

Example

Some solutions for n=4
..1..0..0..1....0..0..0..0....1..0..1..0....1..0..0..0....1..0..0..0
..0..0..0..0....0..1..0..1....0..0..0..0....0..1..0..1....0..0..1..0
..0..0..0..0....0..0..0..0....1..0..0..0....0..0..0..0....0..1..0..0
..1..0..0..0....0..1..0..0....0..0..0..1....0..1..0..1....0..0..0..0

Crossrefs

Sequence in context: A090130 A090140 A032267 * A196196 A266573 A268121

Adjacent sequences: A191474 A191475 A191476 * A191478 A191479 A191480

Keyword

nonn

Author

R. H. Hardin Jun 03 2011

Status

approved