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 A193487 #10 Feb 18 2018 02:49:30 %S A193487 0,0,0,1,1,5,9,29,62,181,422,1166,2885,7788,19893,53319,138931,372027, %T A193487 982379,2635898,7026483,18914903,50781803,137201419,370442111, %U A193487 1004512375,2724867782,7414635185,20193165834,55125632502 %N A193487 Number of rooted trees with n nodes and omega-valency 2. %C A193487 See A003120 for definitions. %H A193487 J.-C. Arditti, <a href="http://dx.doi.org/10.1016/0012-365X(73)90135-0">Dénombrement des arborescences dont le graphe de comparabilité est Hamiltonien</a>, Discrete Math., 5 (1973), 189-200. %Y A193487 Cf. A003120, A193488, A193489, A193490, A193491. %K A193487 nonn %O A193487 1,6 %A A193487 _N. J. A. Sloane_, Jul 27 2011