A105452 - OEIS

%I #10 Sep 25 2020 00:01:16

%S 2,13,20,9,34,41,16,55,62,23,76,83,30,97,104,37,118,125,44,139,146,51,

%T 160,167,58,181,188,65,202,209,72,223,230,79,244,251,86,265,272,93,

%U 286,293,100,307,314,107,328,335,114,349

%N Numerator of (7 n -1)/3.

%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,2,0,0,-1).

%F a(3*n+1) = 7*n+2 = A017005(n), a(3*n+2) = 2*n+13, a(3*n+3) = 21*n+20.

%F From _Chai Wah Wu_, Sep 24 2020: (Start)

%F a(n) = 2*a(n-3) - a(n-6) for n > 6.

%F G.f.: x*(x^5 + 8*x^4 + 5*x^3 + 20*x^2 + 13*x + 2)/(x^6 - 2*x^3 + 1). (End)

%K nonn,frac

%O 1,1

%A _Zak Seidov_, May 02 2005