A182326 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.

1, 1, 10, 1744, 7122884, 932561028624

Offset

1,3

Links

Table of n, a(n) for n=1..6.

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
..3.0.4....0.3.4....3.0.1....3.4.3....0.3.4....3.4.5....3.0.1....0.3.1
..5.1.2.5..5.6.2.0..2.4.3.5..2.0.2.1..1.5.2.5..0.6.7.0..4.5.6.2..4.5.2.5

Crossrefs

Sequence in context: A232594 A194793 A211915 * A370310 A160303 A336666

Adjacent sequences: A182323 A182324 A182325 * A182327 A182328 A182329

Keyword

nonn,more

Author

R. H. Hardin, Apr 24 2012

Status

approved