A212043 Number of lower triangular n X n arrays colored with integers 0 upwards introduced in row major order, with no element equal to any element within a city block distance of two, and containing the value n(n+1)/2-6

0, 0, 5, 463, 339764, 65635205, 3564578765, 89579748909

Offset

1,3

Comments

Column 5 of A212044

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
..3.4.0....3.4.5....3.4.1....3.0.1....3.4.5....3.4.1....3.4.5....3.4.5
..0.5.6.2..5.6.7.8..5.0.3.6..2.4.5.0..2.6.0.4..5.6.3.5..0.6.3.4..6.0.7.3

Crossrefs

Sequence in context: A144509 A240700 A060855 * A182403 A125534 A320958

Adjacent sequences: A212040 A212041 A212042 * A212044 A212045 A212046

Keyword

nonn

Author

R. H. Hardin Apr 28 2012

Status

approved