A192639 Number of n X n symmetric 0..2 arrays with each element equal to at least one horizontal or vertical neighbor and any new values 0..2 introduced in lower triangular row major order

0, 1, 5, 120, 7335, 1156521, 457780079, 457756056728, 1154866876506535, 7352987974445171007, 118143153320894808308264, 4790379823545169735782598423, 490170667588709471795216706934694

Offset

1,3

Links

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

Example

Some solutions for 6X6 containing a 2
..0..0..0..2..2..1....0..0..0..1..1..2....0..0..0..0..2..0....0..0..0..0..0..0
..0..0..0..0..2..1....0..0..0..2..2..2....0..0..0..1..2..0....0..0..0..0..2..2
..0..0..1..1..2..2....0..0..1..1..2..0....0..0..0..1..0..0....0..0..0..1..1..2
..2..0..1..0..0..0....1..2..1..2..2..0....0..1..1..2..2..1....0..0..1..0..0..1
..2..2..2..0..1..1....1..2..2..2..2..0....2..2..0..2..2..1....0..2..1..0..1..1
..1..1..2..0..1..1....2..2..0..0..0..0....0..0..0..1..1..1....0..2..2..1..1..1

Crossrefs

Sequence in context: A158564 A252928 A308363 * A099123 A097993 A172806

Adjacent sequences: A192636 A192637 A192638 * A192640 A192641 A192642

Keyword

nonn

Author

R. H. Hardin Jul 06 2011

Status

approved