A194571 Number of lower triangles of an n X n 0..3 array with new values introduced in row major order 0..3 and no element equal to more than two horizontal or vertical neighbors

1, 5, 178, 39317, 35539864, 123214409287, 1633861873067053, 82861549363088245839, 16072167254492939441649954, 11922831948374582734623213683388

Offset

1,2

Comments

Column 3 of A194576

Links

Table of n, a(n) for n=1..10.

Example

Some solutions for 3X3
..0......0......0......0......0......0......0......0......0......0......0
..1.2....0.1....0.1....1.0....0.1....1.2....1.2....1.1....1.2....1.0....1.2
..1.0.0..0.2.2..1.0.1..1.2.3..0.0.0..2.3.3..1.0.1..1.1.2..3.2.1..1.1.2..1.3.1

Crossrefs

Sequence in context: A200796 A241115 A208196 * A210931 A141981 A136143

Adjacent sequences: A194568 A194569 A194570 * A194572 A194573 A194574

Keyword

nonn

Author

R. H. Hardin Aug 29 2011

Status

approved