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 A100427 #15 Feb 02 2018 17:00:46
%S A100427 1,2,9,48,286,1842,12486,87811,634847,4688676,35221832,268282855,
%T A100427 2067174645,16083734329,126186554308,997171512998,7929819784355,
%U A100427 63411730258053,509588049810620,4113254119923150,33333125878283632,271097737169671824,2212039245722726118
%N A100427 Bisection of A000081 (odd part).
%H A100427 Alois P. Heinz, <a href="/A100427/b100427.txt">Table of n, a(n) for n = 0..400</a>
%p A100427 with(numtheory):
%p A100427 b:= proc(n) option remember; local d, j; `if`(n<2, n,
%p A100427 (add(add(d*b(d), d=divisors(j))*b(n-j), j=1..n-1))/(n-1))
%p A100427 end:
%p A100427 a:= n-> b(2*n+1):
%p A100427 seq(a(n), n=0..50); # _Alois P. Heinz_, May 16 2013
%t A100427 b[n_] := b[n] = If[n <= 1, n, Sum[Sum[d*b[d], {d, Divisors[j]}]*b[n-j], {j, 1, n-1}]/(n-1)]; a[n_] := b[2*n+1]; Table[a[n], {n, 0, 30}] (* _Jean-François Alcover_, Mar 19 2014, after _Alois P. Heinz_ *)
%Y A100427 Cf. A000081, A100034, A299113.
%K A100427 nonn,easy
%O A100427 0,2
%A A100427 _N. J. A. Sloane_, Nov 20 2004
%E A100427 More terms from _Joshua Zucker_, May 12 2006