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 A230284 #15 Jan 08 2021 12:26:20 %S A230284 1,1,2,3,8,15,144,35,5760,315,5600,693,43545600,1001,6706022400,6435, %T A230284 14014,109395,376610217984000,46189,128047474114560000,323323,2540395, %U A230284 2028117,26976017466662584320000,96577,3241475864250624,35102025,2126818694000,5386025 %N A230284 Denominators to Dirichlet inverse of Euler totient based version of series expansion for x/LambertW(x). %H A230284 G. C. Greubel, <a href="/A230284/b230284.txt">Table of n, a(n) for n = 1..385</a> %t A230284 Clear[nn, n, k, s, x]; nn = 22; Denominator[CoefficientList[1 + Integrate[1 + Expand[Sum[Exp[Limit[Zeta[s]*Sum[(If[n == 1, 0, Table[DivisorSum[m, # MoebiusMu[#] &], {m, nn}][[GCD[n, k]]]])/(k)^(s - 1), {k, 1, n}], s -> 1]]*(-x)^n, {n, 1, nn}]], x], x]] %Y A230284 Cf. A191898, A177885, A230283 (numerators). %Y A230284 Similar to but strictly different from A264235. %K A230284 nonn,frac %O A230284 1,3 %A A230284 _Mats Granvik_, Oct 15 2013