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A245867 Number of length n+2 0..6 arrays with some pair in every consecutive three terms totalling exactly 6. 1

%I #8 Nov 04 2018 11:58:23

%S 127,493,1579,5515,18505,63241,214315,729097,2475985,8415217,28590415,

%T 97151683,330100459,1121650903,3811203385,12950003383,44002376953,

%U 149514426895,508030458319,1726221621517,5865476355769,19930126601527

%N Number of length n+2 0..6 arrays with some pair in every consecutive three terms totalling exactly 6.

%H R. H. Hardin, <a href="/A245867/b245867.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) + 3*a(n-2) - a(n-3) - 9*a(n-4) - 24*a(n-5) + 5*a(n-6).

%F Empirical g.f.: x*(127 + 112*x - 281*x^2 - 574*x^3 - 1141*x^4 + 245*x^5) / (1 - 3*x - 3*x^2 + x^3 + 9*x^4 + 24*x^5 - 5*x^6). - _Colin Barker_, Nov 04 2018

%e Some solutions for n=6:

%e ..4....2....1....2....2....5....6....1....2....4....3....4....3....4....6....0

%e ..4....0....1....6....6....4....4....6....1....4....3....2....6....6....0....6

%e ..2....6....5....4....0....1....0....5....5....2....3....3....0....2....1....4

%e ..2....5....2....2....4....5....6....1....1....3....0....3....6....4....5....2

%e ..4....1....1....4....2....1....3....5....1....3....6....6....2....3....1....6

%e ..3....4....4....5....3....2....3....6....5....3....0....0....4....2....5....0

%e ..3....2....5....1....3....5....4....0....0....0....2....2....6....4....1....4

%e ..3....3....2....5....6....1....2....5....1....6....6....6....0....0....4....6

%Y Column 6 of A245869.

%K nonn

%O 1,1

%A _R. H. Hardin_, Aug 04 2014

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