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A247720 Number of length n+3 0..2 arrays with no disjoint pairs in any consecutive four terms having the same sum 1

%I

%S 48,90,172,334,656,1300,2584,5148,10272,20520,41008,81976,163904,

%T 327760,655456,1310832,2621568,5243040,10485952,20971744,41943296,

%U 83886400,167772544,335544768,671089152,1342177920,2684355328,5368710016

%N Number of length n+3 0..2 arrays with no disjoint pairs in any consecutive four terms having the same sum

%C Column 2 of A247726

%H R. H. Hardin, <a href="/A247720/b247720.txt">Table of n, a(n) for n = 1..210</a>

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

%F Empirical G.f.: -2*x*(-24+3*x+4*x^2+5*x^3+54*x^4) / ( (2*x-1)*(2*x^4-1) ). - _R. J. Mathar_, Sep 23 2014

%e Some solutions for n=6

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

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

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

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Sep 23 2014

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Last modified November 29 11:46 EST 2021. Contains 349416 sequences. (Running on oeis4.)