A211915 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, vertical, diagonal or antidiagonal neighbor, and containing the value n(n+1)/2-6

0, 0, 10, 1732, 1085432, 146208485, 6410611003, 140836842878

Offset

1,3

Comments

Column 5 of A211916

Links

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

Example

Some solutions for n=4
..0........0........0........0........0........0........0........0
..1.2......1.2......1.2......1.2......1.2......1.2......1.2......1.2
..3.4.1....3.0.3....0.3.4....3.4.0....3.4.5....3.0.4....0.3.1....3.0.4
..1.0.5.3..2.4.5.6..5.1.6.3..5.1.5.3..2.1.0.3..5.2.6.0..2.4.2.4..4.5.3.6

Crossrefs

Sequence in context: A203530 A232594 A194793 * A182326 A370310 A160303

Adjacent sequences: A211912 A211913 A211914 * A211916 A211917 A211918

Keyword

nonn

Author

R. H. Hardin Apr 25 2012

Status

approved