A247528 - OEIS

%I #8 Nov 07 2018 10:49:14

%S 88,136,220,364,604,1018,1732,2956,5050,8638,14794,25348,43438,74446,

%T 127606,218740,374968,642784,1101898,1888954,3238192,5551168,9516268,

%U 16313584,27966124,47941900,82186078,140890372,241526284,414044950

%N Number of length n+3 0..3 arrays with some disjoint pairs in every consecutive four terms having the same sum.

%H R. H. Hardin, <a href="/A247528/b247528.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) - a(n-3) + a(n-4) - a(n-5) - a(n-6) + a(n-7).

%F Empirical g.f.: 2*x*(44 - 20*x - 26*x^2 + 6*x^3 - 38*x^4 - 9*x^5 + 32*x^6) / ((1 - x)*(1 - x - x^2 - x^4 + x^6)). - _Colin Barker_, Nov 07 2018

%e Some solutions for n=6:

%e ..2....0....2....0....0....2....3....3....2....2....0....1....3....3....0....2

%e ..3....1....0....1....1....3....2....2....1....1....1....1....0....3....1....1

%e ..1....3....1....1....3....1....2....1....2....1....0....0....0....2....1....0

%e ..0....2....3....2....2....2....1....2....3....2....1....2....3....2....2....3

%e ..2....2....2....2....0....0....1....1....2....2....2....1....3....1....0....2

%e ..1....1....0....1....1....1....2....2....1....1....1....3....0....3....1....1

%e ..1....1....1....3....1....1....0....1....2....3....2....0....0....2....1....2

%e ..0....0....1....0....0....2....1....0....3....0....1....2....3....2....2....3

%e ..2....2....2....2....0....2....3....1....2....2....2....1....3....3....0....0

%Y Column 3 of A247533.

%K nonn

%O 1,1

%A _R. H. Hardin_, Sep 18 2014