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 A193034 #12 Jan 19 2022 05:26:42 %S A193034 2,4,1,8,7,3,7,0,6,7,1,8,9,5,5,7,2,5,6,1,4,6,3,7,2,6,6,0,4,3,0,0,2,8, %T A193034 4,4,5,9,4,3,0,2,6,0,9,1,7,6,7,7,4,1,6,4,7,4,7,0,9,9,7,1,2,6,9,3,4,4, %U A193034 9,5,6,7,1,6,2,8,1,7,4,6,6,5,9,4,8,1,4,1,3,9,9,0,9,2,3,0,7,8,6,6 %N A193034 Decimal expansion of the coefficient of x in the reduction of 3^x by x^2->x+1. %C A193034 Reduction of a function f(x) by a substitution q(x)->s(x) is introduced at A193010. %F A193034 From _Amiram Eldar_, Jan 19 2022: (Start) %F A193034 Equals Sum_{k>=0} log(3)^k*Fibonacci(k)/k!. %F A193034 Equals (3^sqrt(5)-1)/(sqrt(5)*3^(phi-1)), where phi is the golden ratio (A001622). (End) %e A193034 2.4187370671895572561463726604300... %t A193034 f[x_] := 3^x; r[n_] := Fibonacci[n]; %t A193034 c[n_] := SeriesCoefficient[Series[f[x], {x, 0, n}], n] %t A193034 u1 = N[Sum[c[n]*r[n], {n, 0, 100}], 100] %t A193034 RealDigits[u1, 10] %Y A193034 Cf. A000045, A001622, A193010, A192232, A193033. %K A193034 nonn,cons %O A193034 1,1 %A A193034 _Clark Kimberling_, Jul 14 2011