A212041 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)/2-4.
0, 0, 5, 319, 14949, 253072, 2326567, 14516200, 69305994, 271885024, 917364452, 2746402607, 7459357270
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....3.4.5....3.4.1....3.4.0....3.0.4....3.4.5....3.4.5....3.0.4 ..5.6.2.5..0.6.7.3..5.0.6.4..5.6.7.2..5.6.3.0..6.0.1.3..0.6.7.1..2.1.5.6
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