A192642 Number of n X n symmetric 0..5 arrays with each element equal to at least one horizontal or vertical neighbor and any new values 0..5 introduced in lower triangular row major order

0, 1, 5, 137, 17687, 14219516, 57958907734, 1047298813289261, 73037304771376915268

Offset

1,3

Links

Table of n, a(n) for n=1..9.

Example

Some solutions for 6X6 containing a 5
..0..0..0..2..3..5....0..0..1..1..4..4....0..0..0..1..2..4....0..0..1..1..4..4
..0..0..0..2..3..5....0..0..0..2..2..4....0..0..0..1..2..4....0..0..0..0..0..5
..0..0..1..1..1..3....1..0..0..3..3..3....0..0..0..1..3..4....1..0..0..2..2..5
..2..2..1..1..1..3....1..2..3..0..0..0....1..1..1..1..3..4....1..0..2..3..3..2
..3..3..1..1..4..4....4..2..3..0..5..5....2..2..3..3..3..5....4..0..2..3..2..2
..5..5..3..3..4..4....4..4..3..0..5..5....4..4..4..4..5..5....4..5..5..2..2..2

Crossrefs

Sequence in context: A012207 A192640 A192641 * A192643 A192644 A134766

Adjacent sequences: A192639 A192640 A192641 * A192643 A192644 A192645

Keyword

nonn

Author

R. H. Hardin Jul 06 2011

Status

approved