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A246478 Number of length n+3 0..7 arrays with no pair in any consecutive four terms totalling exactly 7.

%I A246478 #7 Nov 06 2018 06:44:46
%S A246478 1880,10376,57416,317576,1756472,9714968,53733080,297195272,
%T A246478 1643773832,9091640072,50285457464,278126631896,1538306048600,
%U A246478 8508302434184,47059042885064,260281476168584,1439605284832568,7962392893359512
%N A246478 Number of length n+3 0..7 arrays with no pair in any consecutive four terms totalling exactly 7.
%H A246478 R. H. Hardin, <a href="/A246478/b246478.txt">Table of n, a(n) for n = 1..210</a>
%F A246478 Empirical: a(n) = 5*a(n-1) + 2*a(n-2) + 5*a(n-3) + a(n-4).
%F A246478 Empirical g.f.: 8*x*(235 + 122*x + 222*x^2 + 43*x^3) / (1 - 5*x - 2*x^2 - 5*x^3 - x^4). - _Colin Barker_, Nov 06 2018
%e A246478 Some solutions for n=3:
%e A246478 ..5....0....1....0....2....4....6....0....2....5....6....7....2....7....7....7
%e A246478 ..7....5....0....1....6....0....5....4....1....3....2....3....0....3....6....4
%e A246478 ..5....6....1....4....7....1....6....1....7....1....6....6....3....3....4....7
%e A246478 ..5....6....5....2....6....0....7....0....1....7....7....5....6....1....5....4
%e A246478 ..5....0....0....2....2....2....6....0....5....7....6....5....5....2....4....7
%e A246478 ..1....6....1....6....3....4....2....3....1....5....2....5....3....7....4....5
%Y A246478 Column 7 of A246479.
%K A246478 nonn
%O A246478 1,1
%A A246478 _R. H. Hardin_, Aug 27 2014