A195226 Number of lower triangles of an n X n 0..2 array with each element differing from all of its diagonal, vertical, antidiagonal and horizontal neighbors by one or less

3, 15, 155, 3151, 127785, 10322065, 1663418313, 535153390177, 343932423395227, 441776066934784687, 1134608168927438377475, 5828490619001307113164495, 59904949456032239303490933489, 1232191818850202836476827846621041

Offset

1,1

Comments

Column 2 of A195232

Links

R. H. Hardin, Table of n, a(n) for n = 1..20

Example

Some solutions for n=4
..2........1........1........1........2........2........0........2
..1.1......1.2......1.1......1.2......1.1......1.1......0.0......1.1
..0.1.1....1.1.2....1.1.1....1.2.2....1.1.0....0.1.1....1.0.1....0.0.0
..0.1.1.0..1.1.1.2..0.1.0.0..1.1.2.2..1.1.0.0..0.0.1.1..1.0.0.0..1.1.0.0

Crossrefs

Sequence in context: A245069 A317667 A228901 * A264558 A136519 A102556

Adjacent sequences: A195223 A195224 A195225 * A195227 A195228 A195229

Keyword

nonn

Author

R. H. Hardin Sep 13 2011

Status

approved