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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.

%I A212041 #6 Jun 02 2025 07:54:42
%S A212041 0,0,5,319,14949,253072,2326567,14516200,69305994,271885024,917364452,
%T A212041 2746402607,7459357270
%N 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.
%C A212041 Column 3 of A212044
%e A212041 Some solutions for n=4
%e A212041 ..0........0........0........0........0........0........0........0
%e A212041 ..1.2......1.2......1.2......1.2......1.2......1.2......1.2......1.2
%e A212041 ..3.0.4....3.4.5....3.4.1....3.4.0....3.0.4....3.4.5....3.4.5....3.0.4
%e A212041 ..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
%K A212041 nonn
%O A212041 1,3
%A A212041 _R. H. Hardin_ Apr 28 2012