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 A307661 #5 Apr 21 2019 07:50:57
%S A307661 1,-1,-3,-7,-95,699,-1739,106973,236097,5525495,157003021,-1778692191,
%T A307661 -15439204703,-1112216292877,-2594716702395,-466679409407611,
%U A307661 -2408062589228159,-51920010551722257,965605721357034397,88877767053922329545,2657651357187708962721,161866621274268475146539
%N A307661 E.g.f. A(x) satisfies: A(x) = exp(-x) * A(x^2)^2*A(x^3)^3*A(x^4)^4* ... *A(x^k)^k* ...
%F A307661 E.g.f.: exp(-Sum_{k>=1} A050369(k)*x^k).
%F A307661 a(0) = 1; a(n) = -Sum_{k=1..n} A074206(k)*k*k!*binomial(n-1,k-1)*a(n-k).
%e A307661 E.g.f.: A(x) = 1 - x - 3*x^2/2! - 7*x^3/3! - 95*x^4/4! + 699*x^5/5! - 1739*x^6/6! + 106973*x^7/7! + 236097*x^8/! + 5525495*x^9/9! + ...
%t A307661 terms = 21; A[_] = 1; Do[A[x_] = Exp[-x] Product[A[x^k]^k, {k, 2, terms}] + O[x]^(terms + 1) // Normal, terms + 1]; CoefficientList[A[x], x] Range[0, terms]!
%Y A307661 Cf. A050369, A074206, A307615, A307660.
%K A307661 sign
%O A307661 0,3
%A A307661 _Ilya Gutkovskiy_, Apr 20 2019