A133799 - cp's OEIS frontend

A133799 a(2) = 1, a(3)=3; for n >= 4, a(n) = (n-2)!*Stirling_2(n,n-1)/2 = n!/4.

n	a(n)
2	1
3	3
4	6
5	30
6	180
7	1260
8	10080
9	90720
10	907200
11	9979200
12	119750400
13	1556755200
14	21794572800
15	326918592000
16	5230697472000
17	88921857024000
18	1600593426432000
19	30411275102208000
20	608225502044160000
21	12772735542927360000
22	281000181944401920000

[1, 3, 6, 30, 180, 1260, 10080, 90720, 907200, 9979200, 119750400, 1556755200, 21794572800, 326918592000, 5230697472000, 88921857024000, 1600593426432000, 30411275102208000, 608225502044160000, 12772735542927360000, 281000181944401920000]

cp's OEIS Frontend

A133799 a(2) = 1, a(3)=3; for n >= 4, a(n) = (n-2)!*Stirling_2(n,n-1)/2 = n!/4.

Table of values

List of values