A212032 - OEIS

%I #4 Dec 18 2015 18:18:10

%S 0,3,28,338,2440,11859,43943,134273,355568,843290,1832469,3708583,

%T 7075643,12844948,22348290,37479704,60870173,96100013,147953978,

%U 222724440,328568314,475923713

%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 element at a city block distance of two, and containing the value n(n+1)/2-3

%C Column 2 of A212036

%F Empirical: a(n) = (1/128)*n^8 + (1/32)*n^7 - (53/192)*n^6 - (1/16)*n^5 + (545/128)*n^4 - (1129/96)*n^3 + (913/96)*n^2 + (175/24)*n - 10 for n>1

%e Some solutions for n=4

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

%e ..1.2......0.1......1.2......1.2......1.2......1.2......0.1......1.2

%e ..3.4.5....2.3.4....3.4.4....3.3.0....1.3.4....1.3.4....2.3.4....3.4.5

%e ..6.0.7.6..5.6.2.7..5.6.6.7..4.5.6.7..5.6.7.3..5.6.7.2..5.6.6.7..0.6.7.0

%K nonn

%O 1,2

%A _R. H. Hardin_ Apr 27 2012