A211913 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)/2-4

0, 0, 10, 802, 27963, 394117, 3243531, 18826250, 85484512, 323341343, 1061434357, 3110902786, 8308425940

Offset

1,3

Comments

Column 3 of A211916

Links

Table of n, a(n) for n=1..13.

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
..0.3.4....3.4.5....3.0.4....3.4.0....3.4.5....0.3.4....0.3.4....3.4.5
..5.6.0.5..0.1.6.7..4.5.6.0..5.6.7.6..2.1.6.3..5.2.6.7..4.5.6.1..1.6.2.1

Crossrefs

Sequence in context: A302133 A322918 A233170 * A347845 A006440 A054944

Adjacent sequences: A211910 A211911 A211912 * A211914 A211915 A211916

Keyword

nonn

Author

R. H. Hardin Apr 25 2012

Status

approved