A292108 - cp's OEIS frontend

A292108 Iterate the map k -> (sigma(k) + phi(k))/2 starting at n; a(n) is the number of steps to reach either a fixed point or a fraction, or a(n) = -1 if neither of these two events occurs.

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

[0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 2, 0, 3, 2, 1, 0, 1, 0, 2, 2, 1, 0, 4, 1, 2, 1, 4, 0, 2, 0, 1, 4, 3, 2, 1, 0, 3, 2, 1, 0, 9, 0, 2, 3, 1, 0, 7, 1, 1, 2, 1, 0, 8, 3, 2, 2, 1, 0, 3, 0, 8, 7, 1, 3, 2, 0, 1, 7, 6, 0, 1, 0, 3, 2, 4]

cp's OEIS Frontend

A292108 Iterate the map k -> (sigma(k) + phi(k))/2 starting at n; a(n) is the number of steps to reach either a fixed point or a fraction, or a(n) = -1 if neither of these two events occurs.

Table of values

List of values

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

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

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