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 A159718 #6 May 13 2020 13:01:04
%S A159718 0,0,0,88,33600,3821760,272509552,15313310208,750469872312,
%T A159718 33813251867920,1443455210369040,59454199364673024,
%U A159718 2389923754993613176,94450458835284703536,3687585353084799432720,142691482885508987276800,5484263653598164634676600,209677462059979688650122960
%N A159718 Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 4 local maxima.
%H A159718 Andrew Howroyd, <a href="/A159718/b159718.txt">Table of n, a(n) for n = 1..200</a>
%o A159718 (PARI) \\ CircPeaksBySig defined in A334778.
%o A159718 a(n) = {CircPeaksBySig(vector(n, i, 2), [4])[1]} \\ _Andrew Howroyd_, May 13 2020
%Y A159718 Column 4 of A334778.
%Y A159718 Cf. A159716.
%K A159718 nonn
%O A159718 1,4
%A A159718 _R. H. Hardin_, Apr 20 2009
%E A159718 Terms a(10) and beyond from _Andrew Howroyd_, May 13 2020