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%I #10 Nov 09 2018 21:54:53
%S 204,660,2144,6960,22572,73204,237480,770416,2499164,8107012,26298608,
%T 85311248,276744204,897739412,2912207432,9447011744,30645489228,
%U 99411957620,322485877472,1046123080816,3393554802188,11008469603188
%N Number of length n+3 0..3 arrays with no four consecutive terms having the sum of any three elements equal to three times the fourth.
%H R. H. Hardin, <a href="/A249285/b249285.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + 4*a(n-3) + 8*a(n-4) + 4*a(n-5) - 8*a(n-6) - 2*a(n-7) + 3*a(n-8).
%F Empirical g.f.: 4*x*(51 + 63*x + 104*x^2 + 134*x^3 + 23*x^4 - 133*x^5 - 18*x^6 + 48*x^7) / (1 - 2*x - 2*x^2 - 4*x^3 - 8*x^4 - 4*x^5 + 8*x^6 + 2*x^7 - 3*x^8). - _Colin Barker_, Nov 09 2018
%e Some solutions for n=6:
%e 3 0 3 2 1 1 3 0 0 0 3 3 1 2 0 2
%e 3 1 3 2 0 1 1 0 1 2 1 3 0 3 2 2
%e 1 1 2 1 3 1 3 2 0 2 0 1 1 2 2 1
%e 2 1 3 1 3 0 1 0 2 0 1 1 1 2 0 0
%e 0 0 2 3 1 0 3 2 3 3 3 2 3 0 2 0
%e 2 3 0 3 1 1 0 2 0 1 1 2 0 0 0 1
%e 2 3 1 3 3 0 3 0 1 3 0 0 2 2 2 1
%e 3 0 3 1 3 1 3 3 1 1 2 1 0 3 1 3
%e 3 1 1 1 2 0 3 2 0 2 0 0 0 2 2 0
%Y Column 3 of A249290.
%K nonn
%O 1,1
%A _R. H. Hardin_, Oct 24 2014
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