A182403 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

1, 1, 5, 463, 1092208, 87637302208

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....3.4.5....3.4.0....3.0.4....3.4.0....3.0.4....3.4.5....3.4.5
..4.5.6.0..6.7.1.3..5.6.7.8..5.1.3.5..5.6.7.5..2.5.1.2..6.7.3.0..5.6.3.0

Crossrefs

Sequence in context: A240700 A060855 A212043 * A125534 A320958 A262384

Adjacent sequences: A182400 A182401 A182402 * A182404 A182405 A182406

Keyword

nonn

Author

R. H. Hardin Apr 27 2012

Status

approved