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 A128053 #5 Jun 27 2013 09:57:24 %S A128053 1,-3,-3,7,7,-9,-9,47,47,-123,-123,161,161,-843,-843,2207,2207,-2889, %T A128053 -2889,15127,15127,-39603,-39603,51841,51841,-271443,-271443,710647, %U A128053 710647,-930249,-930249,4870847,4870847,-12752043,-12752043 %N A128053 a(n)=A128056(n)/A128055(n). %F A128053 a(n)=(-1)^C(n+1,2)*(F(n-1)+F(n+1))(5/6-cos(pi*n/3)/3)(1+(-1)^n)/2+(F(n)+F(n+2))(5/6-cos(pi*(n+1)/3)/3)(1-(-1)^n)/2. %F A128053 Empirical g.f.: -(x-1) * (x^10-2*x^9-5*x^8+2*x^7+9*x^6+9*x^4+2*x^3-5*x^2-2*x+1) / ((x^4+3*x^2+1)*(x^8-3*x^6+8*x^4-3*x^2+1)). - _Colin Barker_, Jun 27 2013 %Y A128053 Cf. A128052. %K A128053 easy,sign %O A128053 0,2 %A A128053 _Paul Barry_, Feb 13 2007