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A209729 1/4 the number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having distinct edge sums.

%I A209729 #8 Jul 12 2018 20:26:34
%S A209729 22,124,696,3912,21976,123480,693752,3897880,21900088,123045592,
%T A209729 691329528,3884227224,21823477432,122614931544,688910387576,
%U A209729 3870634114072,21747107494456,122185841630680,686499566270712
%N A209729 1/4 the number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having distinct edge sums.
%C A209729 Column 1 of A209736.
%H A209729 R. H. Hardin, <a href="/A209729/b209729.txt">Table of n, a(n) for n = 1..210</a>
%F A209729 Empirical: a(n) = 3*a(n-1) + 14*a(n-2) + 4*a(n-3).
%F A209729 Empirical g.f.: 2*x*(11 + 29*x + 8*x^2) / (1 - 3*x - 14*x^2 - 4*x^3). - _Colin Barker_, Jul 12 2018
%e A209729 Some solutions for n=4:
%e A209729 ..3..1....1..0....1..2....1..3....1..2....0..0....2..1....1..3....1..0....1..1
%e A209729 ..2..0....1..3....0..2....0..2....3..3....1..2....2..0....0..2....1..3....3..2
%e A209729 ..1..0....2..3....3..2....3..2....1..2....1..3....1..0....3..2....0..2....0..0
%e A209729 ..1..3....1..1....3..0....1..0....0..0....0..2....1..3....3..0....1..2....3..1
%e A209729 ..0..2....0..3....2..0....1..3....1..3....0..1....2..3....3..1....1..3....2..0
%Y A209729 Cf. A209736.
%K A209729 nonn
%O A209729 1,1
%A A209729 _R. H. Hardin_, Mar 12 2012