A212025 Number of lower triangular n X n arrays colored with integers 0 upwards introduced in row major order, with no element equal to any horizontal, diagonal or antidiagonal neighbor, and containing the value n(n+1)/2-6

0, 0, 35, 7396, 2655126, 254601542, 9411294829, 187291345391

Offset

1,3

Comments

Column 5 of A212026

Links

Table of n, a(n) for n=1..8.

Example

Some solutions for n=4
..0........0........0........0........0........0........0........0
..0.1......1.2......1.2......1.2......1.2......1.2......1.2......1.2
..2.1.2....0.3.4....3.4.5....3.4.1....3.4.5....3.2.4....1.2.3....0.3.4
..0.3.4.5..0.2.1.3..3.2.6.4..2.5.3.0..6.2.6.7..4.5.0.3..4.2.5.6..0.1.5.1

Crossrefs

Sequence in context: A025036 A224126 A249888 * A316940 A202066 A271071

Adjacent sequences: A212022 A212023 A212024 * A212026 A212027 A212028

Keyword

nonn

Author

R. H. Hardin Apr 26 2012

Status

approved