A191574 Number of n X n symmetric binary matrices with each 1 adjacent to no more than 6 knight-move neighboring 1s

2, 8, 64, 1024, 31744, 1935544, 233799896, 55948528920, 26536519769600, 24832233133823360, 45900199968106888384, 167513350972291906490904, 1207375485963640678858065184

Offset

1,1

Links

Table of n, a(n) for n=1..13.

Example

Some solutions for n=6
..0..0..0..0..0..0....0..0..0..0..0..0....0..0..0..0..1..1....0..0..0..1..1..0
..0..0..1..0..1..0....0..0..0..1..1..1....0..0..0..1..0..1....0..0..0..1..0..0
..0..1..0..0..0..0....0..0..1..0..0..0....0..0..1..0..1..0....0..0..0..1..1..1
..0..0..0..0..0..0....0..1..0..1..0..0....0..1..0..0..1..0....1..1..1..1..0..0
..0..1..0..0..1..1....0..1..0..0..0..0....1..0..1..1..1..1....1..0..1..0..1..0
..0..0..0..0..1..1....0..1..0..0..0..0....1..1..0..0..1..1....0..0..1..0..0..0

Crossrefs

Sequence in context: A139680 A153544 A153572 * A191575 A153545 A153573

Adjacent sequences: A191571 A191572 A191573 * A191575 A191576 A191577

Keyword

nonn

Author

R. H. Hardin Jun 06 2011

Status

approved