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 A327727 #9 Sep 23 2019 14:03:53 %S A327727 1,2,6,12,28,52,104,184,340,578,1004,1652,2752,4404,7088,11080,17362, %T A327727 26592,40730,61284,92096,136408,201608,294456,428952,618658,889684, %U A327727 1268624,1803520,2545164,3580784,5005584,6976046,9667164,13356364,18360368,25165732 %N A327727 Expansion of Product_{i>=1, j>=0} (1 + x^(i*2^j)) / (1 - x^(i*2^j)). %C A327727 Convolution of the sequences A000041 and A092119. %F A327727 G.f.: Product_{k>=1} ((1 + x^k) / (1 - x^k))^A001511(k). %F A327727 G.f.: Product_{k>=1} 1 / (1 - x^k)^(A001511(k) + 1). %t A327727 nmax = 36; CoefficientList[Series[Product[1/(1 - x^k)^(IntegerExponent[2 k, 2] + 1), {k, 1, nmax}], {x, 0, nmax}], x] %t A327727 a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d (IntegerExponent[2 d, 2] + 1), {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 36}] %o A327727 (PARI) seq(n)={Vec(1/prod(k=1, n, (1 - x^k + O(x*x^n))^(2+valuation(k, 2))))} \\ _Andrew Howroyd_, Sep 23 2019 %Y A327727 Cf. A000041, A001511, A085058, A092119, A170925. %K A327727 nonn %O A327727 0,2 %A A327727 _Ilya Gutkovskiy_, Sep 23 2019