A058971 - cp's OEIS frontend

A058971 For a rational number p/q let f(p/q) = sum of divisors of p+q divided by number of divisors of p+q; a(n) is obtained by iterating f, starting at n/1, until an integer is reached, or if no integer is ever reached then a(n) = 0.

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

[3, 2, 6, 3, 3, 4, 10, 87, 6, 6, 9, 7, 6, 6, 87, 9, 6, 10, 7, 8, 9, 12, 9, 15, 12, 10, 16, 15, 9, 16, 12, 12, 15, 12, 87, 19, 15, 14, 19, 21, 12, 22, 14, 13, 18, 24, 34, 19, 12, 18, 0, 27, 15, 18, 15, 20, 24, 30, 14, 31, 24, 18, 51, 21, 18, 34, 21, 24, 18, 36, 24, 37, 30, 21, 37]

cp's OEIS Frontend

A058971 For a rational number p/q let f(p/q) = sum of divisors of p+q divided by number of divisors of p+q; a(n) is obtained by iterating f, starting at n/1, until an integer is reached, or if no integer is ever reached then a(n) = 0.

Table of values

List of values

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

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

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