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 A220831 #16 Dec 15 2020 12:53:53 %S A220831 0,0,0,3,36,310,2376,17304,123508,874998,6197220,44035861,314538360, %T A220831 2260572810,16353884828,119102737971,873124996284,6441569967712, %U A220831 47813037934740,356947999429560,2679333805629928,20214890317096644,153250432833122904,1167042280999763748 %N A220831 Number of unrooted binary leaf-multi-labeled trees with n leaves on the label set [4], with each label used at least once. %H A220831 Andrew Howroyd, <a href="/A220831/b220831.txt">Table of n, a(n) for n = 1..200</a> %H A220831 V. P. Johnson, <a href="https://people.math.sc.edu/czabarka/Theses/JohnsonThesis.pdf">Enumeration Results on Leaf Labeled Trees</a>, Ph. D. Dissertation, Univ. Southern Calif., 2012. %Y A220831 Column 4 of A339650. %K A220831 nonn %O A220831 1,4 %A A220831 _N. J. A. Sloane_, Dec 22 2012 %E A220831 Terms a(11) and beyond from _Andrew Howroyd_, Dec 14 2020