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 A360988 #15 Jul 06 2025 10:39:46
%S A360988 1,1,-5,-44,829,14656,-488897,-13063616,629051449,22531502080,
%T A360988 -1420908901469,-63859764079616,4983153798630709,269501734545522688,
%U A360988 -25073583375908431769,-1585437525801020801024,171326697778165116452977,12401692280007001315999744
%N A360988 E.g.f. A(x) satisfies A(x) = exp(x * A(-x)^3).
%F A360988 a(n) = Sum_{k=0..n} (3*n - 3*k + 1)^(k-1) * (-3*k)^(n-k) * binomial(n,k).
%F A360988 a(0) = 1; a(n) = (-1)^(n-1) * (n-1)! * Sum_{i, j, k, l>=0 and i+j+k+l=n-1} (-1)^i * (n-i) * a(i) * a(j) * a(k) * a(l)/(i! * j! * k! * l!). - _Seiichi Manyama_, Jul 06 2025
%o A360988 (PARI) a(n) = sum(k=0, n, (3*n-3*k+1)^(k-1)*(-3*k)^(n-k)*binomial(n, k));
%Y A360988 Cf. A141369, A196198, A360987, A360989, A360990.
%Y A360988 Cf. A168601.
%K A360988 sign
%O A360988 0,3
%A A360988 _Seiichi Manyama_, Feb 27 2023