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 A383994 #15 May 28 2025 16:38:00
%S A383994 0,1,-2,0,12,-60,240,-840,1680,15120,-332640,4656960,-59209920,
%T A383994 735134400,-9098369280,112345833600,-1365274310400,15746578848000,
%U A383994 -155630893017600,762963647846400,22567767443020800,-1126188650069683200,35900904478389350400
%N A383994 Series expansion of the exponential generating function exp(wnp^!(x)) - 1 where wnp^!(x) = log(1+x) - x^2/(1+x).
%C A383994 The series wnp^!(x) is the inverse for the substitution of the series wnp(x) (corresponding to A048172), given by the suspension of the Koszul dual of the WithoutNPosets operad. - _Bérénice Delcroix-Oger_, May 28 2025
%H A383994 Michael De Vlieger, <a href="/A383994/b383994.txt">Table of n, a(n) for n = 0..451</a>
%H A383994 Bérénice Delcroix-Oger and Clément Dupont, <a href="https://arxiv.org/abs/2505.06094">Lie-operads and operadic modules from poset cohomology</a>, arXiv:2505.06094 [math.CO], 2025. See p. 32, Table 3, operad without n posets "WNP".
%t A383994 nn = 22; f[x_] := Exp[x] - 1;
%t A383994 Range[0, nn]! * CoefficientList[Series[f[Log[1 + x] - x^2/(1 + x)], {x, 0, nn}], x]
%Y A383994 Cf. A003725, A084099, A097388, A111884, A112242, A177885, A318215, A383990, A383991, A383992, A383993, A383995.
%K A383994 sign
%O A383994 0,3
%A A383994 _Michael De Vlieger_, May 16 2025