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 A089421 #6 Mar 31 2012 14:02:17 %S A089421 1,1,1,2,3,9,22,71,217,729,2438,8440,29414,104138,371516,1337649, %T A089421 4847637,17680265,64823110,238824212,883634026 %N A089421 Number of cycles in range [A014137(n-1)..A014138(n-1)] of permutation A082335/A082336. %C A089421 The number of orbits to which the corresponding automorphism(s) partitions the set of A000108(n) binary trees with n internal nodes. %H A089421 A. Karttunen, <a href="/A089408/a089408.c.txt">C-program for computing the initial terms of this sequence</a> %K A089421 nonn %O A089421 0,4 %A A089421 _Antti Karttunen_, Nov 29 2003