A211962 Number of lower triangular n X n arrays colored with integers 0 upwards introduced in row major order, with no element equal to any diagonal or antidiagonal neighbor, and containing the value n(n+1)/2-6

0, 0, 67, 17947, 5225620, 408588191, 13307423101, 244159057556

Offset

1,3

Comments

Column 5 of A211963

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......1.1......1.2......1.1......1.2......0.1......1.1
..3.3.4....3.2.1....2.3.4....3.4.3....2.3.4....3.0.4....0.1.2....2.2.3
..1.2.5.5..0.4.5.6..5.1.2.0..1.2.5.6..2.1.1.0..1.0.1.0..3.4.4.0..3.4.4.4

Crossrefs

Sequence in context: A280004 A211961 A144940 * A263463 A367903 A279798

Adjacent sequences: A211959 A211960 A211961 * A211963 A211964 A211965

Keyword

nonn

Author

R. H. Hardin Apr 26 2012

Status

approved