A194891 Number of lower triangles of an n X n 0..6 array with new values introduced in row major order 0..6 and no two horizontal or vertical neighbors of any element equal

1, 3, 34, 5249, 7418424, 41521783200, 788547395813440

Offset

1,2

Comments

Column 6 of A194893

Links

Table of n, a(n) for n=1..7.

Example

Some solutions for 4X4
..0........0........0........0........0........0........0........0
..0.1......1.2......0.1......1.1......1.2......1.2......0.1......1.1
..2.2.3....1.3.4....2.3.0....2.3.0....1.3.0....3.3.4....2.3.0....2.3.4
..1.4.5.6..2.0.0.2..4.4.5.2..0.4.1.2..2.4.4.2..2.0.4.1..1.4.2.3..2.3.0.5

Crossrefs

Sequence in context: A102104 A194890 A197434 * A194892 A182382 A222787

Adjacent sequences: A194888 A194889 A194890 * A194892 A194893 A194894

Keyword

nonn

Author

R. H. Hardin Sep 04 2011

Status

approved