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A194535 Number of lower triangles of an n X n 0..3 array with new values introduced in row major order 0..3 and no element equal to more than one horizontal or vertical neighbor.

%I A194535 #8 Jul 22 2025 12:34:39
%S A194535 1,4,116,16556,7721920,11525456507,54979732214116,838387866908847478,
%T A194535 40866499579695484000499,6367568042830726931523028453,
%U A194535 3171485572844765112503023656979959
%N A194535 Number of lower triangles of an n X n 0..3 array with new values introduced in row major order 0..3 and no element equal to more than one horizontal or vertical neighbor.
%C A194535 Column 3 of A194540
%H A194535 R. H. Hardin, <a href="/A194535/b194535.txt">Table of n, a(n) for n = 1..12</a>
%e A194535 Some solutions for 3X3
%e A194535 ..0......0......0......0......0......0......0......0......0......0......0
%e A194535 ..1.2....1.1....1.2....1.2....1.1....1.2....1.2....1.2....1.0....1.2....1.1
%e A194535 ..3.3.0..0.0.2..2.3.1..0.3.0..2.0.1..3.2.1..0.3.1..2.1.3..2.1.2..2.0.1..2.2.1
%K A194535 nonn
%O A194535 1,2
%A A194535 _R. H. Hardin_ Aug 28 2011