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 A047168 #8 Apr 11 2021 22:15:56
%S A047168 0,0,0,0,0,0,0,4,5,25,30,90,105,245,280,588,666,1458,1665,4125,4785,
%T A047168 12705,14850,38830,45331,113399,131859,320411,371735,903175,1048840,
%U A047168 2594540,3021240,7594920,8863698,22366458,26122302,65579982,76575225,191126529
%N A047168 Number of nonempty subsets of {1,2,...,n} in which exactly 4/5 of the elements are <= n/2.
%H A047168 Andrew Howroyd, <a href="/A047168/b047168.txt">Table of n, a(n) for n = 1..500</a>
%F A047168 a(n) = Sum_{k>=1} binomial(floor(n/2), 4*k)*binomial(ceiling(n/2), k). - _Andrew Howroyd_, Apr 11 2021
%o A047168 (PARI) a(n) = {my(m=n\2); sum(k=1, m\4, binomial(m, 4*k)*binomial(n-m, k))} \\ _Andrew Howroyd_, Apr 11 2021
%Y A047168 Cf. A047165.
%K A047168 nonn
%O A047168 1,8
%A A047168 _Clark Kimberling_
%E A047168 Terms a(35) and beyond from _Andrew Howroyd_, Apr 11 2021