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 A152497 #6 May 12 2020 12:54:54
%S A152497 0,0,0,0,2464,744881,104768981,10276536243,822955247485,
%T A152497 58200440129470,3799361321633144,235172542192199514,
%U A152497 14040457016024386686,817688213483194898191,46806533018464413823463,2647280824791216788157413,148469293685889945755890443,8277727866556696292321356900
%N A152497 1/3 of the number of permutations of 2 indistinguishable copies of 1..n with exactly 5 local maxima.
%H A152497 Andrew Howroyd, <a href="/A152497/b152497.txt">Table of n, a(n) for n = 1..200</a>
%F A152497 a(n) = A334774(n,5)/3. - _Andrew Howroyd_, May 12 2020
%o A152497 (PARI) \\ PeaksBySig defined in A334774.
%o A152497 a(n)={PeaksBySig(vector(n,i,2), [4])[1]/3} \\ _Andrew Howroyd_, May 12 2020
%Y A152497 Cf. A334774.
%K A152497 nonn
%O A152497 1,5
%A A152497 _R. H. Hardin_, Dec 06 2008
%E A152497 Terms a(11) and beyond from _Andrew Howroyd_, May 12 2020