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 A339784 #8 Jan 10 2021 02:13:35 %S A339784 1,4,10,20,90,476,3034,21380,163670,1322960,11156014,97142260, %T A339784 868031736,7921646244,73577937258,693691932892,6624644271386, %U A339784 63974219412076,623878427017208,6137012579638796,60836810198042200,607270688878149596,6099719973597772370 %N A339784 Number of homeomorphically irreducible leaf colored trees with n leaves of 4 colors. %H A339784 Andrew Howroyd, <a href="/A339784/b339784.txt">Table of n, a(n) for n = 0..500</a> %o A339784 (PARI) U(25, 4) \\ See A339779 for U(n,k). %Y A339784 Column k=4 of A339779. %K A339784 nonn %O A339784 0,2 %A A339784 _Andrew Howroyd_, Dec 16 2020