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 A036656 #15 Jun 12 2022 03:00:12 %S A036656 0,0,1,1,2,3,6,11,23,46,98,207,451,983,2179,4850,10905,24631,56011, %T A036656 127912,293547,676157,1563372,3626149,8436379,19680277,46026618, %U A036656 107890609,253450711,596572387,1406818759,3323236238,7862958391 %N A036656 Number of n-node rooted unlabeled trees with outdegree <= 2 and exactly 1 edge at the root. %H A036656 <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a> %p A036656 G036656 := G001190-x; A036656 := n->coeff(G036656,x,n); %t A036656 terms = 33; A[_] = 0; Do[A[x_] = x + (1/2)*(A[x]^2 + A[x^2]) + O[x]^terms // Normal, terms]; %t A036656 CoefficientList[A[x] - x, x] (* _Jean-François Alcover_, Jan 24 2018 *) %Y A036656 Except for initial terms, same as A001190. %K A036656 nonn %O A036656 0,5 %A A036656 _N. J. A. Sloane_