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 A257947 #11 Dec 25 2018 22:35:58
%S A257947 1,26,1858,236926,53470032,21496173692,15580846842786,
%T A257947 20666722709050752,50987383226899017116,237747620610010161018672,
%U A257947 2125708489963555363039732518,36886187432874074894930307867796,1253964425811022692146824416678500176
%N A257947 Number of connected graphs with minimum degree at least 3 and with n vertices.
%C A257947 Generating function is K(x,1) in the reference, see page 405.
%D A257947 Miklos Bona, editor, Handbook of Enumerative Combinatorics, CRC Press, 2015, p.404-405.
%H A257947 Vaclav Kotesovec, <a href="/A257947/b257947.txt">Table of n, a(n) for n = 4..80</a>
%F A257947 a(n) ~ 2^(n*(n-1)/2).
%t A257947 Table[n!*SeriesCoefficient[Log[Sum[2^(k*(k-1)/2)*x^k*Exp[k*x*(x-1-k)/(2*(1+x))]/k!, {k, 0, n}]] - x*(2+x+x^2)/(4*(1+x)) - Log[1+x]/2, {x, 0, n}], {n, 4, 15}]
%Y A257947 Cf. A054853, A059166.
%K A257947 nonn
%O A257947 4,2
%A A257947 _Vaclav Kotesovec_, May 14 2015