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 A331114 #11 Jan 30 2020 22:02:43 %S A331114 1,3,37,596,11513,245356,5597060,133950215,3323281496,84787933926, %T A331114 2212123329500,58779046239904,1585796125188065,43337540217740908, %U A331114 1197492197496481744,33406620056723507124,939775084670916268134,26632926871927867655261,759732892913483065912296 %N A331114 Number of rooted trees with 2-colored non-root nodes with an n nodes of each color. %C A331114 The total number of nodes including the root is 2n + 1. %H A331114 Andrew Howroyd, <a href="/A331114/b331114.txt">Table of n, a(n) for n = 0..100</a> %F A331114 a(n) = A304489(2*n+1, n). %e A331114 a(1) = 3 because there are three trees with one root node and one additional node of each color: %e A331114 1 -- o -- 2, %e A331114 o -- 1 -- 2, %e A331114 o -- 2 -- 1. %Y A331114 Cf. A304489, A329055, A331113. %K A331114 nonn %O A331114 0,2 %A A331114 _Andrew Howroyd_, Jan 09 2020