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 A218817 #14 Apr 27 2017 11:53:05
%S A218817 0,1,6,42,352,3470,39468,509544,7367232,117981792,2073609120,
%T A218817 39690563616,821945839680,18312215714832,436766423241120,
%U A218817 11104557643877760,299811706265604096,8566939116183215232,258298187497129564416,8195130059917806607104,272936837532680503188480
%N A218817 Number of rooted factorizations of n-permutations into ordered cycles.
%C A218817 Linearly arrange the cycles over all permutations of {1,2,...,n} (these are called alignments in [Flajolet and Sedgewick]) then select a root.
%H A218817 Alois P. Heinz, <a href="/A218817/b218817.txt">Table of n, a(n) for n = 0..150</a>
%H A218817 Philippe Flajolet and Robert Sedgewick, <a href="http://algo.inria.fr/flajolet/Publications/AnaCombi/anacombi.html">Analytic Combinatorics</a>, Cambridge Univ. Press, 2009, page 119.
%F A218817 E.g.f.: x/( (1-x)*(1 - log(1/(1-x)))^2 ).
%F A218817 a(n) = n*A007840(n).
%p A218817 b:= proc(n) b(n):= n!*`if`(n=0, 1, add(b(k)/(k!*(n-k)), k=0..n-1)) end:
%p A218817 a:= n-> n*b(n):
%p A218817 seq(a(n), n=0..20); # _Alois P. Heinz_, Nov 06 2012
%t A218817 nn=20;a=Log[1/(1-x)];Range[0,nn]!CoefficientList[Series[x D[1/(1-a),x] ,{x,0,nn}],x]
%K A218817 nonn
%O A218817 0,3
%A A218817 _Geoffrey Critzer_, Nov 06 2012