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 A318976 #11 Feb 28 2024 10:49:04 %S A318976 1,2,6,32,196,1512,13384,135872,1545744,19441952,268386784,4018603008, %T A318976 65021744704,1127284876928,20880206388864,410781080941568, %U A318976 8561002328678656,188224613741879808,4355496092560324096,105752112730661347328,2688539359466319184896 %N A318976 Expansion of e.g.f. Product_{k>=1} ((1 + x^k)/(1 - x^k))^(phi(k)/k), where phi is the Euler totient function A000010. %C A318976 Convolution of A088009 and A000262. %H A318976 Vaclav Kotesovec, <a href="/A318976/b318976.txt">Table of n, a(n) for n = 0..440</a> %F A318976 E.g.f.: exp(x*(2 + x)/(1 - x^2)). %F A318976 a(n) ~ 2^(-3/4) * 3^(1/4) * exp(sqrt(6*n) - n - 1/2) * n^(n - 1/4). %t A318976 nmax = 20; CoefficientList[Series[Product[((1+x^k)/(1-x^k))^(EulerPhi[k]/k), {k, 1, nmax}], {x, 0, nmax}], x] * Range[0, nmax]! %t A318976 nmax = 20; CoefficientList[Series[E^(x*(2 + x)/(1 - x^2)), {x, 0, nmax}], x] * Range[0, nmax]! %Y A318976 Cf. A000262, A088009, A318814, A318977. %Y A318976 Cf. A318975, A301555, A301554. %K A318976 nonn %O A318976 0,2 %A A318976 _Vaclav Kotesovec_, Sep 06 2018