login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A006811
as a simple table
n
a(n)
1
4
2
16
3
64
4
246
5
944
6
3532
7
13252
8
48825
[4,16,64,246,944,3532,13252,48825]