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%I A277653 #9 Feb 05 2019 14:21:26
%S A277653 0,0,1,2,8,28,98,346,1218,4290,15110,53218,187438,660170,2325166,
%T A277653 8189402,28843662,101589450,357805342,1260216122,4438571726,
%U A277653 15632968522,55060438334,193926819802,683024192622,2405660280426,8472908349854
%N A277653 Number of n X 2 0..2 arrays with every element equal to some element at offset (-1,0) (-1,1) (0,-1) (0,1) or (1,0) both plus 1 mod 3 and minus 1 mod 3, with new values introduced in order 0..2.
%H A277653 R. H. Hardin, <a href="/A277653/b277653.txt">Table of n, a(n) for n = 1..210</a>
%F A277653 Empirical: a(n) = 3*a(n-1) + 2*a(n-2) - 2*a(n-4).
%F A277653 Empirical g.f.: x^3*(1 - x) / (1 - 3*x - 2*x^2 + 2*x^4). - _Colin Barker_, Feb 05 2019
%e A277653 All solutions for n=4:
%e A277653 ..0..1. .0..1
%e A277653 ..2..2. .2..2
%e A277653 ..1..0. .1..0
%e A277653 ..1..2. .2..1
%Y A277653 Column 2 of A277659.
%K A277653 nonn
%O A277653 1,4
%A A277653 _R. H. Hardin_, Oct 26 2016

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