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 A047169 #8 Apr 11 2021 22:16:01
%S A047169 0,0,0,0,0,0,0,0,4,5,30,36,126,147,392,448,1008,1134,2304,2565,5115,
%T A047169 5687,12342,13860,34320,39039,104104,119119,315679,360815,913640,
%U A047169 1039808,2508928,2842604,6651624,7515054,17505954,19773414,46915104,53093125,129385725,146794494
%N A047169 Number of nonempty subsets of {1,2,...,n} in which exactly 1/6 of the elements are <= n/2.
%H A047169 Andrew Howroyd, <a href="/A047169/b047169.txt">Table of n, a(n) for n = 1..500</a>
%F A047169 a(n) = Sum_{k>=1} binomial(floor(n/2), k)*binomial(ceiling(n/2), 5*k). - _Andrew Howroyd_, Apr 11 2021
%o A047169 (PARI) a(n) = {my(m=n\2); sum(k=1, (n-m)\5, binomial(m, k)*binomial(n-m, 5*k))} \\ _Andrew Howroyd_, Apr 11 2021
%Y A047169 Cf. A047161, A047162, A047170.
%K A047169 nonn
%O A047169 1,9
%A A047169 _Clark Kimberling_
%E A047169 Terms a(35) and beyond from _Andrew Howroyd_, Apr 11 2021