A382986 - cp's OEIS frontend

A382986 a(n) is the number of iterations that n requires to reach 0 under the map k -> b(k) where b(k) = k+1 if k is even, and b(k) = k-gpf(k) if k is odd, where gpf(k) is the greatest prime dividing k.

n	a(n)
0	0
1	1
2	2
3	1
4	2
5	1
6	2
7	1
8	4
9	3
10	2
11	1
12	2
13	1
14	4
15	3
16	2
17	1
18	2
19	1
20	6
21	5
22	2
23	1
24	8
25	7
26	10
27	9
28	2
29	1
30	2
31	1
32	4
33	3
34	4
35	3
36	2
37	1
38	12
39	11
40	2
41	1
42	2
43	1
44	4
45	3
46	2
47	1
48	4
49	3
50	6
51	5
52	2
53	1
54	6
55	5
56	14
57	13
58	2
59	1
60	2
61	1
62	16
63	15
64	4
65	3
66	2
67	1
68	4
69	3
70	2
71	1
72	2
73	1
74	4
75	3
76	4
77	3
78	2
79	1
80	4
81	3
82	2
83	1
84	6
85	5
86	4
87	3
88	2
89	1

[0, 1, 2, 1, 2, 1, 2, 1, 4, 3, 2, 1, 2, 1, 4, 3, 2, 1, 2, 1, 6, 5, 2, 1, 8, 7, 10, 9, 2, 1, 2, 1, 4, 3, 4, 3, 2, 1, 12, 11, 2, 1, 2, 1, 4, 3, 2, 1, 4, 3, 6, 5, 2, 1, 6, 5, 14, 13, 2, 1, 2, 1, 16, 15, 4, 3, 2, 1, 4, 3, 2, 1, 2, 1, 4, 3, 4, 3, 2, 1, 4, 3, 2, 1, 6, 5, 4, 3, 2, 1]

cp's OEIS Frontend

A382986 a(n) is the number of iterations that n requires to reach 0 under the map k -> b(k) where b(k) = k+1 if k is even, and b(k) = k-gpf(k) if k is odd, where gpf(k) is the greatest prime dividing k.

Table of values

List of values

n	a(n)
0	0
1	1
2	2
3	1
4	2
5	1
6	2
7	1
8	4
9	3
10	2
11	1
12	2
13	1
14	4
15	3
16	2
17	1
18	2
19	1
20	6
21	5
22	2
23	1
24	8
25	7
26	10
27	9
28	2
29	1
30	2
31	1
32	4
33	3
34	4
35	3
36	2
37	1
38	12
39	11
40	2
41	1
42	2
43	1
44	4
45	3
46	2
47	1
48	4
49	3
50	6
51	5
52	2
53	1
54	6
55	5
56	14
57	13
58	2
59	1
60	2
61	1
62	16
63	15
64	4
65	3
66	2
67	1
68	4
69	3
70	2
71	1
72	2
73	1
74	4
75	3
76	4
77	3
78	2
79	1
80	4
81	3
82	2
83	1
84	6
85	5
86	4
87	3
88	2
89	1

n	a(n)
0	0
1	1
2	2
3	1
4	2
5	1
6	2
7	1
8	4
9	3
10	2
11	1
12	2
13	1
14	4
15	3
16	2
17	1
18	2
19	1
20	6
21	5
22	2
23	1
24	8
25	7
26	10
27	9
28	2
29	1
30	2
31	1
32	4
33	3
34	4
35	3
36	2
37	1
38	12
39	11
40	2
41	1
42	2
43	1
44	4
45	3
46	2
47	1
48	4
49	3
50	6
51	5
52	2
53	1
54	6
55	5
56	14
57	13
58	2
59	1
60	2
61	1
62	16
63	15
64	4
65	3
66	2
67	1
68	4
69	3
70	2
71	1
72	2
73	1
74	4
75	3
76	4
77	3
78	2
79	1
80	4
81	3
82	2
83	1
84	6
85	5
86	4
87	3
88	2
89	1

n	a(n)
0	0
1	1
2	2
3	1
4	2
5	1
6	2
7	1
8	4
9	3
10	2
11	1
12	2
13	1
14	4
15	3
16	2
17	1
18	2
19	1
20	6
21	5
22	2
23	1
24	8
25	7
26	10
27	9
28	2
29	1
30	2
31	1
32	4
33	3
34	4
35	3
36	2
37	1
38	12
39	11
40	2
41	1
42	2
43	1
44	4
45	3
46	2
47	1
48	4
49	3
50	6
51	5
52	2
53	1
54	6
55	5
56	14
57	13
58	2
59	1
60	2
61	1
62	16
63	15
64	4
65	3
66	2
67	1
68	4
69	3
70	2
71	1
72	2
73	1
74	4
75	3
76	4
77	3
78	2
79	1
80	4
81	3
82	2
83	1
84	6
85	5
86	4
87	3
88	2
89	1