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 A059221 #6 Jul 11 2015 00:13:34 %S A059221 1,1,2,4,8,18,43,103,255,642,1640,4242,11096,29278,77882,208589, %T A059221 562056,1522606,4144521,11329608,31090910,85618848,236530942, %U A059221 655344579,1820585313,5070138554,14151907583,39584395796,110938500821,311481097178 %N A059221 Number of 3-bead necklaces where each bead is an unlabeled rooted tree, by total number of nodes. %Y A059221 See A058855 (the 6-bead analog) for details. %K A059221 nonn %O A059221 0,3 %A A059221 _N. J. A. Sloane_, Jan 18 2001