A194993 Number of lower triangles of an n X n 0..3 array with each element differing from all of its horizontal and vertical neighbors by one.

4, 10, 42, 248, 2290, 31042, 641376, 19753266, 918924546, 64065187024, 6724991990090, 1059952700132050, 251257954485037072, 89488725743024413554, 47916300899545924260762, 38558096411377540692559456

Offset: 1

Author

R. H. Hardin Sep 07 2011

Keywords

• nonn

Comments

Column 3 of A194998

Examples

			Some solutions for 4X4
..1........3........2........3........1........2........1........3
..2.3......2.1......1.2......2.1......0.1......3.2......2.1......2.3
..1.2.3....1.2.3....2.1.2....3.2.3....1.2.3....2.1.2....1.2.1....3.2.1
..0.1.2.3..0.1.2.3..3.2.3.2..2.3.2.3..2.3.2.1..3.2.1.2..2.1.2.3..2.1.0.1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..32