A122685 - cp's OEIS frontend

A122685 a(n) = n! except that a(2) = -2 and a(2n) = 0 for n > 2.

n	a(n)
0	1
1	1
2	-2
3	6
4	0
5	120
6	0
7	5040
8	0
9	362880
10	0
11	39916800
12	0
13	6227020800
14	0
15	1307674368000
16	0
17	355687428096000
18	0
19	121645100408832000
20	0
21	51090942171709440000
22	0
23	25852016738884976640000
24	0
25	15511210043330985984000000
26	0
27	10888869450418352160768000000
28	0
29	8841761993739701954543616000000

[1, 1, -2, 6, 0, 120, 0, 5040, 0, 362880, 0, 39916800, 0, 6227020800, 0, 1307674368000, 0, 355687428096000, 0, 121645100408832000, 0, 51090942171709440000, 0, 25852016738884976640000, 0, 15511210043330985984000000, 0, 10888869450418352160768000000, 0, 8841761993739701954543616000000]

cp's OEIS Frontend

A122685 a(n) = n! except that a(2) = -2 and a(2n) = 0 for n > 2.

Table of values

List of values