A191570 Number of n X n symmetric binary matrices with each 1 adjacent to no more than 2 knight-move neighboring 1s.

2, 8, 64, 608, 8404, 216892, 9337976, 632108017, 67457332362, 11825770678093, 3349770239089324, 1533187995312783695, 1132523827035520870024

Offset

1,1

Links

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

Example

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

Crossrefs

Sequence in context: A354276 A353821 A354237 * A052707 A059862 A268666

Adjacent sequences: A191567 A191568 A191569 * A191571 A191572 A191573

Keyword

nonn

Author

R. H. Hardin, Jun 06 2011

Status

approved