A384874 - cp's OEIS frontend

A384874 a(n) is the first prime encountered when iterating the map x -> x/2 if x is even, x*lpf(x) + 1 otherwise, where lpf(x) is the least prime factor of x, on n >= 2; or -1 if a prime is never reached.

n	a(n)
2	2
3	3
4	2
5	5
6	3
7	7
8	2
9	7
10	5
11	11
12	3
13	13
14	7
15	23
16	2
17	17
18	7
19	19
20	5
21	2
22	11
23	23
24	3
25	313
26	13
27	41
28	7
29	29
30	23
31	31
32	2
33	313
34	17
35	11
36	7
37	37
38	19
39	59
40	5
41	41
42	2
43	43
44	11
45	17
46	23
47	47
48	3
49	43
50	313
51	5869
52	13
53	53
54	41
55	13
56	7
57	43
58	29
59	59
60	23
61	61
62	31
63	313
64	2
65	163
66	313
67	67
68	17
69	13
70	11

[2, 3, 2, 5, 3, 7, 2, 7, 5, 11, 3, 13, 7, 23, 2, 17, 7, 19, 5, 2, 11, 23, 3, 313, 13, 41, 7, 29, 23, 31, 2, 313, 17, 11, 7, 37, 19, 59, 5, 41, 2, 43, 11, 17, 23, 47, 3, 43, 313, 5869, 13, 53, 41, 13, 7, 43, 29, 59, 23, 61, 31, 313, 2, 163, 313, 67, 17, 13, 11]

cp's OEIS Frontend

A384874 a(n) is the first prime encountered when iterating the map x -> x/2 if x is even, x*lpf(x) + 1 otherwise, where lpf(x) is the least prime factor of x, on n >= 2; or -1 if a prime is never reached.

Table of values

List of values