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 A306768 #12 Apr 14 2019 07:51:31
%S A306768 0,1,1,-1,-2,2,6,-5,-18,15,59,-54,-215,199,813,-744,-3135,2890,12394,
%T A306768 -11538,-50017,46806,204893,-192451,-849681,800974,3560927,-3367656,
%U A306768 -15058478,14279426,64171736,-60992032,-275304665,262199050,1188070488,-1133572891,-5153913606
%N A306768 G.f. A(x) satisfies: A(x) = x*exp(-A(-x) + A(-x^2)/2 - A(-x^3)/3 + A(-x^4)/4 - A(-x^5)/5 + ...).
%F A306768 G.f.: A(x) = Sum_{n>=1} a(n)*x^n = x * Product_{n>=1} 1/(1 + x^n)^((-1)^n*a(n)).
%F A306768 Recurrence: a(n+1) = (1/n) * Sum_{k=1..n} ( Sum_{d|k} (-1)^(k/d+d)*d*a(d) ) * a(n-k+1).
%e A306768 G.f.: A(x) = x + x^2 - x^3 - 2*x^4 + 2*x^5 + 6*x^6 - 5*x^7 - 18*x^8 + 15*x^9 + 59*x^10 - 54*x^11 - 215*x^12 + ...
%t A306768 terms = 36; A[_] = 0; Do[A[x_] = x Exp[Sum[(-1)^k A[-x^k]/k, {k, 1, terms}]] + O[x]^(terms + 1) // Normal, terms + 1]; CoefficientList[A[x], x]
%t A306768 a[n_] := a[n] = SeriesCoefficient[x Product[1/(1 + x^k)^((-1)^k a[k]), {k, 1, n - 1}], {x, 0, n}]; a[0] = 0; Table[a[n], {n, 0, 36}]
%Y A306768 Cf. A000081, A004111, A045648, A049075, A073075, A115593, A307365, A307366, A307538.
%K A306768 sign
%O A306768 0,5
%A A306768 _Ilya Gutkovskiy_, Apr 14 2019