A387140 - cp's OEIS frontend

A387140 a(n) = (1/n) * Product_{k=1..n} radical(k) for n >= 1, a(0) = 1, where radical(n) is the product of distinct prime factors of n, cf. A007947.

n	a(n)
0	1
1	1
2	1
3	2
4	3
5	12
6	60
7	360
8	630
9	1680
10	15120
11	151200
12	831600
13	9979200
14	129729600
15	1816214400
16	3405402000
17	54486432000
18	308756448000
19	5557616064000
20	52797352608000
21	1055947052160000
22	22174888095360000
23	487847538097920000
24	2805123344063040000
25	13464592051502592000

[1, 1, 1, 2, 3, 12, 60, 360, 630, 1680, 15120, 151200, 831600, 9979200, 129729600, 1816214400, 3405402000, 54486432000, 308756448000, 5557616064000, 52797352608000, 1055947052160000, 22174888095360000, 487847538097920000, 2805123344063040000, 13464592051502592000]

cp's OEIS Frontend

A387140 a(n) = (1/n) * Product_{k=1..n} radical(k) for n >= 1, a(0) = 1, where radical(n) is the product of distinct prime factors of n, cf. A007947.

Table of values

List of values