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 A300274 #6 Mar 01 2018 14:53:48 %S A300274 2,2,6,10,22,30,62,86,146,206,342,454,726,974,1442,1962,2862,3762, %T A300274 5398,7094,9834,12942,17726,22938,31042,40094,53254,68518,90246, %U A300274 114914,150142,190550,245906,310942,398554,500474,637590,797534,1007714,1255850,1578526,1956786 %N A300274 G.f.: 1 + Sum_{n>=1} a(n)*x^n/(1 - x^n) = Product_{n>=1} (1 + x^n)/(1 - x^n). %C A300274 Moebius transform of A015128. %H A300274 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a> %F A300274 a(n) = Sum_{d|n} mu(n/d)*A015128(d). %t A300274 nn = 42; f[x_] := 1 + Sum[a[n] x^n/(1 - x^n), {n, 1, nn}]; sol = SolveAlways[0 == Series[f[x] - Product[(1 + x^n)/(1 - x^n), {n, 1, nn}], {x, 0, nn}], x]; Table[a[n], {n, 1, nn}] /. sol // Flatten %t A300274 s[n_] := SeriesCoefficient[Product[(1 + x^k)/(1 - x^k), {k, 1, n}], {x, 0, n}]; a[n_] := Sum[MoebiusMu[n/d] s[d], {d, Divisors[n]}]; Table[a[n], {n, 1, 42}] %Y A300274 Cf. A000837, A015128, A078374, A300275, A300276, A300277, A300278. %K A300274 nonn %O A300274 1,1 %A A300274 _Ilya Gutkovskiy_, Mar 01 2018