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Number of length n binary sequences with at most 3 of every 6 adjacent bits set.
8

%I #10 May 30 2020 23:12:05

%S 1,2,4,8,15,26,42,74,132,236,421,747,1314,2318,4101,7263,12864,22773,

%T 40291,71272,126099,223144,394895,698823,1236609,2188185,3872000,

%U 6851631,12124307,21454602,37964931,67180507,118878510,210360283,372241362,658697067

%N Number of length n binary sequences with at most 3 of every 6 adjacent bits set.

%H Alois P. Heinz, <a href="/A133551/b133551.txt">Table of n, a(n) for n = 0..2000</a>

%H <a href="/index/Rec#order_20">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,0,0,1,3,0,-3,-1,0,0,-3,-1,3,0,0,0,1,0,-1).

%F G.f.: -(x^19 +x^18 -x^16 -x^15 -3*x^13 -2*x^12 +2*x^11 +4*x^10 +2*x^9 +x^8 +4*x^7 +4*x^6 -2*x^5 -3*x^4 -2*x^3 -x^2-x-1) / ((x-1) *(x+1) *(x^18 -3*x^12 +x^11 +x^9 +2*x^7 +3*x^6 +2*x^5 +x^3 +x -1)). - _Alois P. Heinz_, May 29 2020

%K nonn,easy

%O 0,2

%A _R. H. Hardin_, Dec 24 2007