login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A227769
as a simple table
n
a(n)
1
6
2
20
3
252
4
468996
5
0
6
0
7
0
[6,20,252,468996,0,0,0]