A194781 Number of lower triangles of a (2n+1)X(2n+1) 0..n array with new values introduced in row major order 0..n and no element unequal to more than one horizontal or vertical neighbor.

6, 41, 265, 1736, 11857, 85007, 639753, 5045602, 41615156, 358185389, 3210667479, 29914284821, 289187621887

Offset: 1

Author

R. H. Hardin Sep 02 2011

Keywords

• nonn

Comments

Row 3 of A194778

Examples

			Some solutions for n=2 containing a 2
..0..........0..........0..........0..........0..........0..........0
..1.1........1.1........1.1........0.0........1.1........1.1........0.1
..1.1.2......1.1.1......1.1.1......1.1.1......1.1.1......1.1.2......0.1.1
..1.1.2.2....1.1.1.1....1.1.1.2....1.1.1.1....2.2.2.2....1.1.2.2....0.1.1.1
..1.1.2.2.1..2.2.2.2.2..1.1.1.2.2..1.1.1.1.2..2.2.2.2.0..1.1.2.2.0..0.1.1.1.2