A211914 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, diagonal or antidiagonal neighbor, and containing the value n(n+1)/2-5.
0, 0, 10, 1492, 227388, 9345480, 172044141, 1908272916, 14931819099
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 ..3.0.4....3.4.0....3.4.3....3.4.5....0.3.4....0.3.1....3.4.0....3.0.4 ..1.5.3.1..5.1.6.4..5.6.5.1..0.6.0.6..5.6.5.2..2.4.0.5..1.5.6.5..1.2.1.5
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