login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A216661
as a simple table
n
a(n)
1
2
2
25
3
780
4
59799
5
8990804
6
2315439963
7
928319229295
[2,25,780,59799,8990804,2315439963,928319229295]