A212042 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)/2-5.
0, 0, 5, 447, 94131, 5054845, 109065807, 1339229741, 11235618109
Offset: 1
Keywords
Examples
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....3.0.4....3.4.0....3.0.4....3.4.5....3.4.5....3.0.4....3.4.5 ..0.5.3.4..5.1.2.5..5.6.3.5..5.6.7.5..5.0.6.2..2.1.0.2..5.1.6.2..6.7.2.1
Comments