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 A339525 #18 Dec 21 2020 15:19:31
%S A339525 0,0,0,1,3,8,19,47,119,309,805,2115,5594,14920,40037,108068,293124,
%T A339525 798739,2185380,6001797,16538728,45716315,126727586,352214041,
%U A339525 981269274,2739925455,7666335708,21491822234,60358497108,169798015580,478420350367
%N A339525 Number of unordered pairs of rooted trees with a total of n nodes and an odd total of leaves.
%C A339525 Equivalently, the number of rooted trees on n+1 nodes, where the root has degree 2, and the number of leaves is odd.
%C A339525 To get a pair of trees with an odd number of leaves one tree must have an even number of leaves and the other an odd number of leaves.
%H A339525 Washington Bomfim, <a href="/A339525/a339525.png">Illustration of initial terms</a>
%H A339525 <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a>
%F A339525 a(n) = Sum_{k=1, n-1}( A253013(k) * A253014(n-k) ).
%Y A339525 Cf. A253013, A253014, A339524.
%K A339525 nonn
%O A339525 1,5
%A A339525 _Washington Bomfim_, Dec 08 2020