A384698 - cp's OEIS frontend

A384698 The first prime number reached by iterating the map, x -> 2*x + 1 if x is even; x - lpf(x) 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	13
5	5
6	13
7	7
8	17
9	13
10	37
11	11
12	41
13	13
14	29
15	41
16	61
17	17
18	37
19	19
20	41
21	37
22	613
23	23
24	613
25	41
26	53
27	613
28	109
29	29
30	61
31	31
32	829
33	61
34	1861
35	61
36	73
37	37
38	277
39	73
40	157
41	41
42	613
43	43
44	89
45	613
46	181
47	47
48	97
49	613
50	101
51	97
52	401
53	53
54	109
55	101
56	113
57	109
58	229
59	59
60	829
61	61
62	241

[2, 3, 13, 5, 13, 7, 17, 13, 37, 11, 41, 13, 29, 41, 61, 17, 37, 19, 41, 37, 613, 23, 613, 41, 53, 613, 109, 29, 61, 31, 829, 61, 1861, 61, 73, 37, 277, 73, 157, 41, 613, 43, 89, 613, 181, 47, 97, 613, 101, 97, 401, 53, 109, 101, 113, 109, 229, 59, 829, 61, 241]

cp's OEIS Frontend

A384698 The first prime number reached by iterating the map, x -> 2*x + 1 if x is even; x - lpf(x) 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