A337643 - cp's OEIS frontend

A337643 a(1) = 1; thereafter a(n) = a(n-1) / lpf(n) if lpf(n) divides a(n-1), otherwise a(n) = a(n-1) * lpf(n), where lpf is the least prime factor function A020639.

n	a(n)
1	1
2	1
3	2
4	6
5	3
6	15
7	30
8	210
9	105
10	35
11	70
12	770
13	385
14	5005
15	10010
16	30030
17	15015
18	255255
19	510510
20	9699690
21	4849845
22	1616615
23	3233230
24	74364290
25	37182145
26	7436429
27	14872858
28	44618574
29	22309287
30	646969323
31	1293938646
32	40112098026
33	20056049013
34	6685349671
35	13370699342

[1, 1, 2, 6, 3, 15, 30, 210, 105, 35, 70, 770, 385, 5005, 10010, 30030, 15015, 255255, 510510, 9699690, 4849845, 1616615, 3233230, 74364290, 37182145, 7436429, 14872858, 44618574, 22309287, 646969323, 1293938646, 40112098026, 20056049013, 6685349671, 13370699342]

cp's OEIS Frontend

A337643 a(1) = 1; thereafter a(n) = a(n-1) / lpf(n) if lpf(n) divides a(n-1), otherwise a(n) = a(n-1) * lpf(n), where lpf is the least prime factor function A020639.

Table of values

List of values