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 A205969 #14 Jul 18 2018 06:43:37 %S A205969 1,-2,4,-4,6,0,32,-52,84,-68,0,0,288,-932,3016,0,1974,0,10336,-16724, %T A205969 0,-43784,0,0,185472,-150050,971144,-392836,1271244,0,0,-5385076, %U A205969 8713236,0,0,0,29860704,-96631268,312705352,-252983944,0,0,2143314368,-1733977748,0 %N A205969 a(n) = Fibonacci(n)*A113973(n) for n>=1, with a(0)=1, where A113973 lists the coefficients in phi(x^3)^3/phi(x) and phi() is a Ramanujan theta function. %C A205969 Compare g.f. to the Lambert series of A113973: 1 - 2*Sum_{n>=1} Kronecker(n,3)*x^n/(1 - (-x)^n). %H A205969 G. C. Greubel, <a href="/A205969/b205969.txt">Table of n, a(n) for n = 0..2500</a> %F A205969 G.f.: 1 - 2*Sum_{n>=1} Fibonacci(n)*Kronecker(n,3)*x^n/(1 - Lucas(n)*(-x)^n + (-1)^n*x^(2*n)). %e A205969 G.f.: A(x) = 1 - 2*x + 4*x^2 - 4*x^3 + 6*x^4 + 32*x^6 - 52*x^7 + 84*x^8 +... %e A205969 where A(x) = 1 - 1*2*x + 1*4*x^2 - 2*2*x^3 + 3*2*x^4 + 8*4*x^6 - 13*4*x^7 + 21*4*x^8 +...+ Fibonacci(n)*A113973(n)*x^n +... %e A205969 The g.f. is also given by the identity: %e A205969 A(x) = 1 - 2*( 1*x/(1+x-x^2) - 1*x^2/(1-3*x^2+x^4) + 3*x^4/(1-7*x^4+x^8) - 5*x^5/(1+11*x^5-x^10) + 13*x^7/(1+29*x^7-x^14) - 21*x^8/(1-47*x^8+x^16) +...). %e A205969 The values of the symbol Kronecker(n,3) repeat [1,-1,0, ...]. %t A205969 A113973:= CoefficientList[Series[EllipticTheta[3, q^3]^3/EllipticTheta[3, 0, q], {q, 0, 75}], q]; Table[If[n == 1, 1, Fibonacci[n-1]*A113973[[n]] ], {n, 1, 50}] (* _G. C. Greubel_, Jul 17 2018 *) %o A205969 (PARI) {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)} %o A205969 {a(n)=polcoeff(1 - 2*sum(m=1,n,fibonacci(m)*kronecker(m,3)*x^m/(1-Lucas(m)*(-x)^m+(-1)^m*x^(2*m) +x*O(x^n))),n)} %o A205969 for(n=0,60,print1(a(n),", ")) %Y A205969 Cf. A113973, A205966, A205968, A205970, A203847, A000204 (Lucas). %Y A205969 Cf. A209449 (Pell variant). %K A205969 sign %O A205969 0,2 %A A205969 _Paul D. Hanna_, Feb 04 2012