A182335 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 or antidiagonal neighbor

1, 2, 27, 6097, 31863051, 5224775238844, 34790236871289428139

Offset

1,2

Links

Table of n, a(n) for n=1..7.

Example

Some solutions for n=4
..0........0........0........0........0........0........0........0
..1.2......1.2......1.2......1.0......1.2......1.2......1.2......1.0
..0.1.3....3.1.0....3.0.1....2.3.4....3.4.1....0.1.3....3.4.1....2.3.4
..2.4.2.3..4.3.1.0..4.5.6.1..4.0.1.5..0.5.4.6..3.0.2.1..5.6.3.5..4.1.0.5

Crossrefs

Sequence in context: A320669 A299116 A076113 * A362288 A056013 A363403

Adjacent sequences: A182332 A182333 A182334 * A182336 A182337 A182338

Keyword

nonn

Author

R. H. Hardin Apr 25 2012

Status

approved