A192995 Number of n X n symmetric 0..1 arrays with each element equal to at least two horizontal or vertical neighbors and with new values 0..1 introduced in lower triangular row major order

0, 1, 1, 5, 24, 184, 2052, 34481, 852317, 31436448, 1719054683, 139749375352, 16887682211105, 3032513808121101, 809442991768500676, 321179427812462958357, 189437827654558885755438

Offset

1,4

Links

R. H. Hardin, Table of n, a(n) for n = 1..19

Example

Some solutions for 8X8 containing a 1
..0..0..0..0..0..0..0..0....0..0..0..0..1..1..0..0....0..0..0..0..0..0..0..0
..0..0..1..1..0..0..0..0....0..1..1..0..1..1..0..0....0..1..1..1..1..1..0..0
..0..1..1..1..0..0..1..1....0..1..1..0..1..1..1..0....0..1..1..1..1..1..0..0
..0..1..1..1..1..0..1..1....0..0..0..0..0..1..1..0....0..1..1..1..0..0..0..0
..0..0..0..1..1..0..1..1....1..1..1..0..0..1..1..0....0..1..1..0..0..1..1..0
..0..0..0..0..0..0..0..1....1..1..1..1..1..1..0..0....0..1..1..0..1..1..1..0
..0..0..1..1..1..0..0..1....0..0..1..1..1..0..0..0....0..0..0..0..1..1..1..0
..0..0..1..1..1..1..1..1....0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0

Crossrefs

Sequence in context: A184597 A009601 A009676 * A027851 A120765 A259355

Adjacent sequences: A192992 A192993 A192994 * A192996 A192997 A192998

Keyword

nonn

Author

R. H. Hardin Jul 14 2011

Status

approved