A002217 - cp's OEIS frontend

A002217 Starting with n, repeatedly calculate the sum of prime factors (with repetition) of the previous term, until reaching 0 or a fixed point: a(n) is the number of terms in the resulting sequence.

n	a(n)
1	2
2	1
3	1
4	1
5	1
6	2
7	1
8	3
9	3
10	2
11	1
12	2
13	1
14	4
15	4
16	4
17	1
18	4
19	1
20	4
21	3
22	2
23	1
24	4
25	3
26	5
27	4
28	2
29	1
30	3
31	1
32	3
33	5
34	2
35	3
36	3
37	1
38	4
39	5
40	2
41	1
42	3
43	1
44	5
45	2
46	4
47	1
48	2
49	5
50	3
51	5
52	2
53	1
54	2
55	5
56	2
57	3
58	2
59	1
60	3
61	1
62	6
63	2
64	3
65	5
66	5
67	1
68	4
69	6
70	5
71	1
72	3
73	1
74	6
75	2
76	2
77	5
78	5
79	1
80	2
81	3
82	2
83	1
84	5
85	3
86	3
87	4
88	2
89	1
90	2
91	5
92	5
93	3
94	6
95	5
96	2
97	1
98	5
99	2
100	5
101	1
102	3
103	1
104	2
105	5

[2, 1, 1, 1, 1, 2, 1, 3, 3, 2, 1, 2, 1, 4, 4, 4, 1, 4, 1, 4, 3, 2, 1, 4, 3, 5, 4, 2, 1, 3, 1, 3, 5, 2, 3, 3, 1, 4, 5, 2, 1, 3, 1, 5, 2, 4, 1, 2, 5, 3, 5, 2, 1, 2, 5, 2, 3, 2, 1, 3, 1, 6, 2, 3, 5, 5, 1, 4, 6, 5, 1, 3, 1, 6, 2, 2, 5, 5, 1, 2, 3, 2, 1, 5, 3, 3, 4, 2, 1, 2, 5, 5, 3, 6, 5, 2, 1, 5, 2, 5, 1, 3, 1, 2, 5]

cp's OEIS Frontend

A002217 Starting with n, repeatedly calculate the sum of prime factors (with repetition) of the previous term, until reaching 0 or a fixed point: a(n) is the number of terms in the resulting sequence.

Table of values

List of values

n	a(n)
1	2
2	1
3	1
4	1
5	1
6	2
7	1
8	3
9	3
10	2
11	1
12	2
13	1
14	4
15	4
16	4
17	1
18	4
19	1
20	4
21	3
22	2
23	1
24	4
25	3
26	5
27	4
28	2
29	1
30	3
31	1
32	3
33	5
34	2
35	3
36	3
37	1
38	4
39	5
40	2
41	1
42	3
43	1
44	5
45	2
46	4
47	1
48	2
49	5
50	3
51	5
52	2
53	1
54	2
55	5
56	2
57	3
58	2
59	1
60	3
61	1
62	6
63	2
64	3
65	5
66	5
67	1
68	4
69	6
70	5
71	1
72	3
73	1
74	6
75	2
76	2
77	5
78	5
79	1
80	2
81	3
82	2
83	1
84	5
85	3
86	3
87	4
88	2
89	1
90	2
91	5
92	5
93	3
94	6
95	5
96	2
97	1
98	5
99	2
100	5
101	1
102	3
103	1
104	2
105	5

n	a(n)
1	2
2	1
3	1
4	1
5	1
6	2
7	1
8	3
9	3
10	2
11	1
12	2
13	1
14	4
15	4
16	4
17	1
18	4
19	1
20	4
21	3
22	2
23	1
24	4
25	3
26	5
27	4
28	2
29	1
30	3
31	1
32	3
33	5
34	2
35	3
36	3
37	1
38	4
39	5
40	2
41	1
42	3
43	1
44	5
45	2
46	4
47	1
48	2
49	5
50	3
51	5
52	2
53	1
54	2
55	5
56	2
57	3
58	2
59	1
60	3
61	1
62	6
63	2
64	3
65	5
66	5
67	1
68	4
69	6
70	5
71	1
72	3
73	1
74	6
75	2
76	2
77	5
78	5
79	1
80	2
81	3
82	2
83	1
84	5
85	3
86	3
87	4
88	2
89	1
90	2
91	5
92	5
93	3
94	6
95	5
96	2
97	1
98	5
99	2
100	5
101	1
102	3
103	1
104	2
105	5

n	a(n)
1	2
2	1
3	1
4	1
5	1
6	2
7	1
8	3
9	3
10	2
11	1
12	2
13	1
14	4
15	4
16	4
17	1
18	4
19	1
20	4
21	3
22	2
23	1
24	4
25	3
26	5
27	4
28	2
29	1
30	3
31	1
32	3
33	5
34	2
35	3
36	3
37	1
38	4
39	5
40	2
41	1
42	3
43	1
44	5
45	2
46	4
47	1
48	2
49	5
50	3
51	5
52	2
53	1
54	2
55	5
56	2
57	3
58	2
59	1
60	3
61	1
62	6
63	2
64	3
65	5
66	5
67	1
68	4
69	6
70	5
71	1
72	3
73	1
74	6
75	2
76	2
77	5
78	5
79	1
80	2
81	3
82	2
83	1
84	5
85	3
86	3
87	4
88	2
89	1
90	2
91	5
92	5
93	3
94	6
95	5
96	2
97	1
98	5
99	2
100	5
101	1
102	3
103	1
104	2
105	5