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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 or antidiagonal neighbor, and containing the value n(n+1)/2-5
0

%I #4 Dec 18 2015 18:18:09

%S 0,0,27,4151,425384,14087170,230476122,2379082308,17753221488

%N 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 or antidiagonal neighbor, and containing the value n(n+1)/2-5

%C Column 4 of A211930

%e Some solutions for n=4

%e ..0........0........0........0........0........0........0........0

%e ..1.2......1.2......1.2......1.2......1.2......1.2......1.2......1.2

%e ..3.4.0....0.3.1....3.4.0....3.4.5....0.3.4....3.4.5....3.4.0....3.4.3

%e ..1.5.6.7..4.2.0.5..2.5.4.2..5.0.1.4..5.6.1.0..0.1.4.0..1.5.4.5..5.2.0.5

%K nonn

%O 1,3

%A _R. H. Hardin_ Apr 25 2012