login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A111189
as a simple table
n
a(n)
1
1
2
2
3
3
4
9
5
20
6
75
7
255
[1,2,3,9,20,75,255]