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 A122206 #5 Mar 31 2012 13:21:32 %S A122206 1,1,2,5,17,66,307,1619,9668,64112,469936,3773496,32997159,312542002, %T A122206 3192352420,35023164817,411288004670,5154265796088,68746349160704, %U A122206 973526723323087,14605620692012861,231694886107899371 %N A122206 Number of sequences b with last index n with b(0) = 1, b(i+1) = b(i)+d where d|b(i). %C A122206 b(n) can be as large as 2^n. [From _Max Alekseyev_, May 10 2009] %e A122206 For n=3, the sequences are 1,2,3,4; 1,2,3,6; 1,2,4,5; 1,2,4,6; and 1,2,4,8. We can't have 1,2,3,5 because the difference (5-3) does not divide 3. %Y A122206 Cf. A117497, A122205. %K A122206 nonn %O A122206 0,3 %A A122206 _Franklin T. Adams-Watters_, Aug 25 2006 %E A122206 a(15)..a(21) from _Max Alekseyev_, May 10 2009