A007661 - cp's OEIS frontend

A007661 Triple factorial numbers a(n) = n!!!, defined by a(n) = n*a(n-3), a(0) = a(1) = 1, a(2) = 2. Sometimes written n!3.

n	a(n)
0	1
1	1
2	2
3	3
4	4
5	10
6	18
7	28
8	80
9	162
10	280
11	880
12	1944
13	3640
14	12320
15	29160
16	58240
17	209440
18	524880
19	1106560
20	4188800
21	11022480
22	24344320
23	96342400
24	264539520
25	608608000
26	2504902400
27	7142567040
28	17041024000
29	72642169600
30	214277011200
31	528271744000
32	2324549427200

[1, 1, 2, 3, 4, 10, 18, 28, 80, 162, 280, 880, 1944, 3640, 12320, 29160, 58240, 209440, 524880, 1106560, 4188800, 11022480, 24344320, 96342400, 264539520, 608608000, 2504902400, 7142567040, 17041024000, 72642169600, 214277011200, 528271744000, 2324549427200]

cp's OEIS Frontend

A007661 Triple factorial numbers a(n) = n!!!, defined by a(n) = n*a(n-3), a(0) = a(1) = 1, a(2) = 2. Sometimes written n!3.

Table of values

List of values