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 A229652 #10 Oct 22 2015 14:49:00
%S A229652 1,4,28,232,2092,19864,195352,1970896,20275660,211823800,2240795848,
%T A229652 23951289564,258255473032,2805534386256,30675481454184,
%U A229652 337306578693652,3727580774618060,41376921517941032,461122691909043112,5157400529078643552
%N A229652 Cogrowth function of the group Baumslag-Solitar(10,10).
%C A229652 a(n) is the number of words of length 2n in the letters a,a^{-1},t,t^{-1} that equal the identity of the group BS(10,10)=<a,t | ta^{10}=a^{10}t>.
%H A229652 Murray Elder, <a href="/A229652/b229652.txt">Table of n, a(n) for n = 0..50</a>
%H A229652 M. Elder, A. Rechnitzer, E. J. Janse van Rensburg, T. Wong, <a href="http://arxiv.org/abs/1309.4184">The cogrowth series for BS(N,N) is D-finite</a>
%H A229652 <a href="/index/Gre#groups">Index entries for sequences related to groups</a>
%e A229652 For n=1 there are 4 words of length 2 equal to the identity: aa^{-1}, a^{-1}a, tt^{-1}, t^{-1}t.
%Y A229652 The cogrowth sequences for BS(N,N) for N = 1..10 are A002894, A229644, A229645, A229646, A229647, A229648, A229649, A229650, A229651, A229652.
%K A229652 nonn,walk
%O A229652 0,2
%A A229652 _Murray Elder_, Sep 28 2013