A194992 Number of lower triangles of an n X n 0..2 array with each element differing from all of its horizontal and vertical neighbors by one.

3, 6, 20, 80, 576, 4608, 69632, 1114112, 34603008, 1107296256, 69793218560, 4466765987840, 567347999932416, 72620543991349248, 18518801667747479552, 4740813226943354765312, 2422574005712127994626048

Offset: 1

Author

R. H. Hardin, Sep 07 2011

Keywords

• nonn

Comments

Column 2 of A194998.

Examples

			Some solutions for 4 X 4
..2........1........0........2........0........0........0........0
..1.0......2.1......1.2......1.0......1.0......1.0......1.0......1.0
..2.1.2....1.2.1....0.1.0....2.1.2....2.1.0....0.1.0....2.1.0....2.1.0
..1.0.1.0..2.1.2.1..1.2.1.0..1.2.1.0..1.2.1.2..1.0.1.2..1.2.1.0..1.0.1.2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..89

Crossrefs

Cf. A194998.