login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A040174
as a simple table
n
a(n)
1
1
2
4
3
2
4
8
5
40
6
120
7
168
8
6720
9
120960
10
44800
11
6652800
12
14515200
13
415134720
[1,4,2,8,40,120,168,6720,120960,44800,6652800, 14515200,415134720]