A006595 - cp's OEIS frontend

A006595 a(n) = (n+2)!/4 + n!/2.

n	a(n)
0	1
1	2
2	7
3	33
4	192
5	1320
6	10440
7	93240
8	927360
9	10160640
10	121564800
11	1576713600
12	22034073600
13	330032102400
14	5274286617600
15	89575694208000
16	1611054821376000
17	30589118816256000
18	611426688897024000
19	12833558093131776000
20	282216632948490240000

[1, 2, 7, 33, 192, 1320, 10440, 93240, 927360, 10160640, 121564800, 1576713600, 22034073600, 330032102400, 5274286617600, 89575694208000, 1611054821376000, 30589118816256000, 611426688897024000, 12833558093131776000, 282216632948490240000]

cp's OEIS Frontend

A006595 a(n) = (n+2)!/4 + n!/2.

Table of values

List of values