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 A334775 #9 Jan 11 2021 00:14:42
%S A334775 1,3,24,339,7392,230217,9689934,529634931,36463272996,3086776079745,
%T A334775 315108659732034,38170141911313467,5412679282489599840,
%U A334775 888197438344278978537,166988574370806672234630,35659091146526471860555587,8583030980293328579564829948,2312892203852608268226402385617
%N A334775 Number of permutations of 2 indistinguishable copies of 1..n with exactly n local maxima.
%H A334775 Andrew Howroyd, <a href="/A334775/b334775.txt">Table of n, a(n) for n = 1..100</a>
%o A334775 (PARI) \\ PeaksBySig defined in A334774.
%o A334775 a(n)={ PeaksBySig(vector(n,i,2), [n-1])[1] }
%Y A334775 Main diagonal of A334774.
%K A334775 nonn
%O A334775 1,2
%A A334775 _Andrew Howroyd_, May 11 2020