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 A152513 #10 Jul 16 2020 12:11:40
%S A152513 0,5,497,42581,3584693,301183841,25300030889,2125207418285,
%T A152513 178517461842461,14995467100301177,1259619238806161681,
%U A152513 105808016078078472389,8887873350698981879429,746581361459780256986513,62712834362629583374730873,5267878086460945365330876893
%N A152513 1/21 of the number of permutations of 6 indistinguishable copies of 1..n with exactly 2 local maxima.
%H A152513 Andrew Howroyd, <a href="/A152513/b152513.txt">Table of n, a(n) for n = 1..200</a>
%H A152513 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (98,-1225,4116).
%F A152513 a(n) = (61*84^(n-1) - 61*7^(n-1) - 66*(n-1)*7^(n-1))/847. - _Andrew Howroyd_, May 10 2020
%F A152513 From _Colin Barker_, Jul 16 2020: (Start)
%F A152513 G.f.: x^2*(5 + 7*x) / ((1 - 7*x)^2*(1 - 84*x)).
%F A152513 a(n) = 98*a(n-1) - 1225*a(n-2) + 4116*a(n-3) for n>3.
%F A152513 (End)
%o A152513 (PARI) a(n) = {(61*84^(n-1) - 61*7^(n-1) - 66*(n-1)*7^(n-1))/847} \\ _Andrew Howroyd_, May 10 2020
%o A152513 (PARI) Vec(x^2*(5 + 7*x) / ((1 - 7*x)^2*(1 - 84*x)) + O(x^18)) \\ _Colin Barker_, Jul 16 2020
%Y A152513 Cf. A152494, A334773.
%K A152513 nonn,easy
%O A152513 1,2
%A A152513 _R. H. Hardin_, Dec 06 2008
%E A152513 Terms a(7) and beyond from _Andrew Howroyd_, May 10 2020