%I #7 Dec 18 2015 18:18:03
%S 1,13,8469,99752346,16567902881244,38625516979536823947,
%T 1263976383376771173195964686,580579239138791881884932674640711196,
%U 3743190521310525744113304412007474906812935048
%N Number of n X n 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors
%C Diagonal of A208175
%H R. H. Hardin, <a href="/A208169/b208169.txt">Table of n, a(n) for n = 1..10</a>
%e Some solutions for n=4
%e ..0..0..0..0....0..0..0..1....0..1..0..0....0..0..0..1....0..0..0..0
%e ..0..1..1..2....1..1..0..0....2..2..1..2....1..0..1..2....1..1..1..1
%e ..1..0..1..3....2..3..3..0....1..1..3..2....2..2..1..0....2..1..2..3
%e ..1..3..3..1....0..2..1..3....0..3..0..0....0..3..0..1....0..1..2..0
%K nonn
%O 1,2
%A _R. H. Hardin_ Feb 24 2012