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 A334776 #9 May 20 2020 02:43:40
%S A334776 0,3,105,4620,283500,23700600,2610808200,367783416000,64607286744000,
%T A334776 13859305059600000,3567385122341040000,1085582734152396480000,
%U A334776 385634331725066424000000,158175715893528308976000000,74203019661816956710800000000,39481403043334753112451840000000
%N A334776 Total number of peaks in all permutations of 2 indistinguishable copies of 1..n.
%H A334776 Andrew Howroyd, <a href="/A334776/b334776.txt">Table of n, a(n) for n = 1..100</a>
%F A334776 a(n) = Sum_{k=1..n} (k-1)*A334774(n,k).
%F A334776 a(n) = A334777(n) - A000680(n).
%o A334776 (PARI) \\ PeaksBySig defined in A334774.
%o A334776 a(n)={my(u=PeaksBySig(vector(n,i,2), [0..n-1])); sum(k=1, #u, (k-1)*u[k])}
%Y A334776 Cf. A000680, A334774, A334775, A334777.
%K A334776 nonn
%O A334776 1,2
%A A334776 _Andrew Howroyd_, May 12 2020