%I #6 Dec 18 2015 18:17:46
%S 1,5,162,17424,6756437,9790899054,53438526965463,1095434478598715742,
%T 84189100478450762470628,24264818647445156524051251366,
%U 26234269948355443957604222160170467
%N Number of lower triangles of an n X n 0..3 array with no element greater than the number its nonzero horizontal and vertical neighbors
%H R. H. Hardin, <a href="/A195950/b195950.txt">Table of n, a(n) for n = 1..16</a>
%e Some solutions for n=4
%e ..1........1........1........0........1........1........0........0
%e ..2.1......2.0......3.2......0.1......1.1......3.2......2.2......1.2
%e ..1.2.0....3.3.2....1.3.0....2.1.2....3.2.2....2.1.1....1.1.1....1.1.1
%e ..0.2.1.1..2.1.1.1..2.1.1.0..2.2.1.1..1.3.2.0..1.2.3.1..2.2.2.1..0.2.1.0
%K nonn
%O 1,2
%A _R. H. Hardin_ Sep 25 2011