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 A097630 #16 Feb 24 2019 16:40:04
%S A097630 1,1,7,70,1093,22426,578779,17976302,653866441,27270138898,
%T A097630 1283303262151,67277393090854,3888789288662029,245724292311198650,
%U A097630 16851817924083466003,1246663922538961356766,98960637955717312632721
%N A097630 Number of unrooted directed trees on n nodes with a red root.
%H A097630 Andrew Howroyd, <a href="/A097630/b097630.txt">Table of n, a(n) for n = 1..200</a>
%H A097630 C. Banderier, J.-M. Le Bars and V. Ravelomanana, <a href="http://arxiv.org/abs/math.CO/0411138">Generating functions for kernels of digraphs</a>
%F A097630 E.g.f.: A(x) = 2B - 2BC + C - 2B/C + C^2/2, with B = egf of A052746 and C = egf of A097627.
%F A097630 a(n) = (n-1)!*[x^n](LambertW(-LambertW(-2x)/2)). - _Jean-François Alcover_, Dec 13 2018
%F A097630 a(n) ~ 2^n * n^(n-2) / (1 + 1/LambertW(1/2)). - _Vaclav Kotesovec_, Feb 24 2019
%t A097630 terms = 17;
%t A097630 Rest[CoefficientList[LambertW[-LambertW[-2x]/2] + O[x]^(terms+1), x]]* Range[0, terms-1]! (* _Jean-François Alcover_, Dec 13 2018 *)
%o A097630 (PARI) seq(n)={Vec(serlaplace(lambertw(-lambertw(-2*x + O(x*x^n))/2)/x))} \\ _Andrew Howroyd_, Dec 13 2018
%Y A097630 Cf. A097629.
%K A097630 nonn
%O A097630 1,3
%A A097630 _Ralf Stephan_, Aug 17 2004