A212034 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 at a city block distance of two, and containing the value n(n+1)/2-5

0, 0, 34, 3967, 373930, 12302859, 203628239, 2132961900, 16137269619

Offset

1,3

Comments

Column 4 of A212036

Links

Table of n, a(n) for n=1..9.

Example

Some solutions for n=4
..0........0........0........0........0........0........0........0
..1.2......1.2......1.2......1.2......1.2......1.1......1.2......0.1
..3.3.4....1.3.3....3.3.4....3.4.1....1.3.3....2.3.4....1.3.4....2.1.3
..5.6.6.2..4.5.5.4..0.1.5.5..5.5.2.3..4.0.5.4..2.3.5.0..0.5.4.0..4.0.0.5

Crossrefs

Sequence in context: A258499 A218718 A129056 * A297072 A232900 A209943

Adjacent sequences: A212031 A212032 A212033 * A212035 A212036 A212037

Keyword

nonn

Author

R. H. Hardin Apr 27 2012

Status

approved