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 A319013 #29 Nov 30 2019 02:06:36
%S A319013 0,1,7,37,201,1231,8653,69273,623521,6235291,68588301,823059733,
%T A319013 10699776673,149796873591,2246953104061,35951249665201,
%U A319013 611171244308673,11001082397556403,209020565553571981,4180411311071439981,87788637532500240001,1931350025715005280463
%N A319013 a(n) is the sum over each permutation of S_n of the least element of the descent set.
%C A319013 a(1) = 0 since the descent set of the identity permutation is empty.
%C A319013 Lim_{n->infinity} a(n)/n! = e - 1.
%D A319013 R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 1, 2011; see Section 1.4, pp. 38.
%H A319013 Peter Kagey, <a href="/A319013/b319013.txt">Table of n, a(n) for n = 1..400</a>
%F A319013 a(n) = Sum_{k=1..n-1} k^2*binomial(n, k+1)*(n - k - 1)!.
%F A319013 a(n+1) = (n+1)*a(n) + n^2, with a(1) = 0.
%F A319013 a(n) = A002627(n) - n.
%e A319013 For n = 3, the least element of the descent set for each permutation in S_3 is given by the table:
%e A319013 +-------------+-------------+----------------------+
%e A319013 | permutation | descent set | least element (or 0) |
%e A319013 +-------------+-------------+----------------------+
%e A319013 | 123 | {} | 0 |
%e A319013 | 132 | {2} | 2 |
%e A319013 | 213 | {1} | 1 |
%e A319013 | 231 | {2} | 2 |
%e A319013 | 312 | {1} | 1 |
%e A319013 | 321 | {1,2} | 1 |
%e A319013 +-------------+-------------+----------------------+
%e A319013 Thus a(3) = 0 + 2 + 1 + 2 + 1 + 1 = 7.
%t A319013 Table[Sum[k^2*Binomial[n, k + 1]*(n - k - 1)!, {k, 1, n - 1}], {n, 1, 15}]
%o A319013 (PARI) a(n) = sum(k=1, n-1, k^2*binomial(n, k+1)*(n-k-1)!); \\ _Michel Marcus_, Nov 28 2019
%Y A319013 Cf. A002627.
%K A319013 nonn
%O A319013 1,3
%A A319013 _Peter Kagey_, Sep 07 2018