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 A052120 #13 Feb 16 2025 08:32:41 %S A052120 1,1,0,1,0,1,0,1,0,2,0,2,0,4,0,6,0,11,0,18,0,37,0,66,0,135,0,265,0, %T A052120 552,0,1132,0,2410,0,5098,0,11020,0,23846,0 %N A052120 Number of 3-valent trees (= boron trees or binary trees) with n nodes. %C A052120 Trees with n nodes each of valency either 1 or 3. %H A052120 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CayleyTree.html">Cayley Tree.</a> %H A052120 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TrivalentTree.html">Trivalent Tree</a> %H A052120 <a href="/index/Tra#trees">Index entries for sequences related to trees</a> %Y A052120 See A000672, the subsequence of even-numbered terms, which is the main entry for this sequence, for more terms, references, etc. %K A052120 nonn,easy %O A052120 1,10 %A A052120 _N. J. A. Sloane_