cp's OEIS Frontend

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.

A347994 a(n) = n! * Sum_{k=1..n-1} (-1)^(k+1) * n^(n-k-2) / (n-k-1)!.

Table of values

n a(n)
1 0
2 1
3 4
4 30
5 296
6 3720
7 56652
8 1014832
9 20909520
10 487198080
11 12667470740
12 363607605504
13 11420819358456
14 389646915374080
15 14349217119054300
16 567315485527234560
17 23967624180805666208
18 1077568488585047605248
19 51369752823292604784420
20 2588268388538639982592000

List of values

[0, 1, 4, 30, 296, 3720, 56652, 1014832, 20909520, 487198080, 12667470740, 363607605504, 11420819358456, 389646915374080, 14349217119054300, 567315485527234560, 23967624180805666208, 1077568488585047605248, 51369752823292604784420, 2588268388538639982592000]