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 A323673 #10 Jan 29 2019 05:00:14
%S A323673 0,1,0,2,7,69,696,9400,148506,2753793,58255840,1388008566,36768832200,
%T A323673 1072407094693,34151921130432,1179292944433500,43892264744070736,
%U A323673 1751768399754149025,74633720517351765504,3380997879130123703818,162286529338732345488000,8227876237310253918100581
%N A323673 Expansion of e.g.f. log(1 - LambertW(-x)*(2 + LambertW(-x))/2).
%F A323673 E.g.f.: log(1 + Sum_{k>=1} k^(k-2)*x^k/k!).
%F A323673 a(0) = 0; a(n) = A000272(n) - (1/n)*Sum_{k=1..n-1} binomial(n,k)*A000272(n-k)*k*a(k).
%F A323673 a(n) ~ 2 * n^(n-2) / 3. - _Vaclav Kotesovec_, Jan 24 2019
%p A323673 seq(n!*coeff(series(log(1-LambertW(-x)*(2+LambertW(-x))/2),x=0,22),x,n),n=0..21); # _Paolo P. Lava_, Jan 28 2019
%t A323673 nmax = 21; CoefficientList[Series[Log[1 - LambertW[-x] (2 + LambertW[-x])/2], {x, 0, nmax}], x] Range[0, nmax]!
%t A323673 a[n_] := a[n] = n^(n - 2) - Sum[Binomial[n, k] (n - k)^(n - k - 2) k a[k], {k, 1, n - 1}]/n; a[0] = 0; Table[a[n], {n, 0, 21}]
%Y A323673 Cf. A000272, A001858, A001865, A133297.
%K A323673 nonn
%O A323673 0,4
%A A323673 _Ilya Gutkovskiy_, Jan 23 2019