A191571 Number of n X n symmetric binary matrices with each 1 adjacent to no more than 3 knight-move neighboring 1s

2, 8, 64, 775, 12956, 435303, 27256988, 2944205484, 528310229714, 165642950895264, 90217673507084286

Offset

1,1

Links

Table of n, a(n) for n=1..11.

Example

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

Crossrefs

Sequence in context: A136282 A092934 A224801 * A347012 A139679 A005640

Adjacent sequences: A191568 A191569 A191570 * A191572 A191573 A191574

Keyword

nonn

Author

R. H. Hardin Jun 06 2011

Status

approved