This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A105452 #10 Sep 25 2020 00:01:16 %S A105452 2,13,20,9,34,41,16,55,62,23,76,83,30,97,104,37,118,125,44,139,146,51, %T A105452 160,167,58,181,188,65,202,209,72,223,230,79,244,251,86,265,272,93, %U A105452 286,293,100,307,314,107,328,335,114,349 %N A105452 Numerator of (7 n -1)/3. %H A105452 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,2,0,0,-1). %F A105452 a(3*n+1) = 7*n+2 = A017005(n), a(3*n+2) = 2*n+13, a(3*n+3) = 21*n+20. %F A105452 From _Chai Wah Wu_, Sep 24 2020: (Start) %F A105452 a(n) = 2*a(n-3) - a(n-6) for n > 6. %F A105452 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 A105452 nonn,frac %O A105452 1,1 %A A105452 _Zak Seidov_, May 02 2005