login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A003489
as a simple table
n
a(n)
1
4
2
20
3
84
4
292
5
980
6
3052
7
9316
8
27396
9
79412
[4,20,84,292,980,3052,9316,27396,79412]