%I #4 Mar 31 2012 12:36:21
%S 0,1,21,1093,172217,81613877,113899763795,468482952092893,
%T 5676720267644621509
%N Number of nXnXn triangular 0..2 arrays with each element equal to the sum mod 3 of two neighbors
%e Some solutions for 4X4X4
%e .....1........0........0........1........1........0........2........0
%e ....2.2......2.1......1.2......1.0......2.2......1.2......1.1......2.1
%e ...2.1.2....1.0.2....1.2.1....0.2.0....1.1.2....0.1.1....2.1.0....2.0.1
%e ..2.0.1.0..2.1.1.0..1.0.1.2..0.0.1.1..2.1.2.1..2.2.0.1..0.1.0.0..0.1.1.2
%K nonn
%O 1,3
%A _R. H. Hardin_ Jul 16 2011