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A208195 Number of n X 2 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than two of its immediate leftward or upward or left-upward diagonal neighbors.

%I A208195 #8 Jun 29 2018 06:02:52
%S A208195 2,14,178,2653,41272,648569,10215440,160984657,2537249104,39990174809,
%T A208195 630298266416,9934351303777,156578831693200,2467894630281641,
%U A208195 38897365218137072,613075213064694577,9662896575843028048
%N A208195 Number of n X 2 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than two of its immediate leftward or upward or left-upward diagonal neighbors.
%C A208195 Column 2 of A208201.
%H A208195 R. H. Hardin, <a href="/A208195/b208195.txt">Table of n, a(n) for n = 1..210</a>
%F A208195 Empirical: a(n) = 18*a(n-1) - 31*a(n-2) - 66*a(n-3) - 24*a(n-4) for n>5.
%F A208195 Empirical g.f.: x*(2 - 22*x - 12*x^2 + 15*x^3 + 8*x^4) / ((1 - 3*x - 2*x^2)*(1 - 15*x - 12*x^2)). - _Colin Barker_, Jun 29 2018
%e A208195 Some solutions for n=4:
%e A208195 ..0..0....0..0....0..0....0..0....0..0....0..0....0..1....0..0....0..0....0..1
%e A208195 ..0..1....1..0....1..1....1..0....1..0....0..1....1..1....0..1....0..1....1..0
%e A208195 ..0..0....2..0....0..1....1..0....0..0....0..0....0..0....0..2....1..0....0..0
%e A208195 ..1..2....1..2....0..0....0..1....0..1....0..2....0..1....1..3....2..2....2..0
%Y A208195 Cf. A208201.
%K A208195 nonn
%O A208195 1,1
%A A208195 _R. H. Hardin_, Feb 24 2012