A194925 Number of lower triangles of an n X n 0..2 array with no element differing from any of its horizontal or vertical neighbors by more than one.

3, 17, 217, 5873, 344091, 43337009, 11761200209, 6872287575297, 8648230733328339, 23436303828484483825, 136773087470228122215081, 1718926116885238623987854577, 46522215573069867474481754034859

Offset

1,1

Comments

Column 2 of A194931.

Links

R. H. Hardin, Table of n, a(n) for n = 1..21

Example

Some solutions for 4 X 4
..2........1........2........0........0........0........0........1
..1.2......1.0......1.1......1.2......0.1......0.1......1.0......0.1
..2.1.1....1.0.0....0.1.0....2.1.2....1.2.2....1.1.2....0.0.0....0.1.0
..2.2.1.1..0.0.0.0..0.0.0.1..1.2.2.2..1.1.1.2..2.2.1.2..0.1.1.1..1.0.1.1

Crossrefs

Cf. A194931.

Sequence in context: A009494 A267659 A075271 * A072350 A181032 A331649

Adjacent sequences: A194922 A194923 A194924 * A194926 A194927 A194928

Keyword

nonn

Author

R. H. Hardin, Sep 05 2011

Status

approved