A002691 - cp's OEIS frontend

A002691 a(n) = (n+2) * (2n+1) * (2n-1)! / (n-1)!.

n	a(n)
0	1
1	9
2	120
3	2100
4	45360
5	1164240
6	34594560
7	1167566400
8	44108064000
9	1843717075200
10	84475764172800
11	4209708914611200
12	226676633863680000
13	13114862387827200000
14	811372819726909440000
15	53449184499510159360000
16	3735154775612827607040000

[1, 9, 120, 2100, 45360, 1164240, 34594560, 1167566400, 44108064000, 1843717075200, 84475764172800, 4209708914611200, 226676633863680000, 13114862387827200000, 811372819726909440000, 53449184499510159360000, 3735154775612827607040000]

cp's OEIS Frontend

A002691 a(n) = (n+2) * (2n+1) * (2n-1)! / (n-1)!.

Table of values

List of values