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 A066351 #14 Dec 22 2016 17:29:22
%S A066351 1,2,5,14,43,140,472,1628,5719,20388,73562,268066,984911,3643570,
%T A066351 13557020,50691978,190353370,717457656,2713061899,10289600164,
%U A066351 39127877886,149147692734,569767908076,2180978471298,8363866011929,32129445138352,123618810558184
%N A066351 Bisection of A007059.
%D A066351 R. Kemp, Balanced ordered trees, Random Structures and Algorithms, 5, 1994, 99-121.
%H A066351 Alois P. Heinz, <a href="/A066351/b066351.txt">Table of n, a(n) for n = 0..500</a>
%F A066351 Conjecture: a(n) ~ 0.721... * 4^n / n. - _Vaclav Kotesovec_, Aug 25 2014
%p A066351 b:= proc(n, m) option remember; `if`(n=0, 1,
%p A066351 `if`(m=0, add(b(n-j, j), j=1..n),
%p A066351 add(b(n-j, min(n-j, m)), j=1..min(n, m))))
%p A066351 end:
%p A066351 a:= n-> b(2*n, 0):
%p A066351 seq(a(n), n=0..40); # _Alois P. Heinz_, May 13 2014
%t A066351 b[n_, m_] := b[n, m] = If[n == 0, 1, If[m == 0, Sum[b[n - j, j], {j, 1, n} ], Sum[b[n - j, Min[n - j, m]], {j, 1, Min[n, m]}]]]; a[n_] := b[2*n, 0]; Table[a[n], {n, 0, 40}] (* _Jean-François Alcover_, Dec 22 2016, after _Alois P. Heinz_ *)
%K A066351 nonn,easy
%O A066351 0,2
%A A066351 _N. J. A. Sloane_, Dec 19 2001
%E A066351 More terms from _Emeric Deutsch_, Jun 10 2004