login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A198861
as a simple table
n
a(n)
1
2
2
30
3
1680
4
7983360
5
40548366802944000
[2,30,1680,7983360,40548366802944000]