A082991 - cp's OEIS frontend

A082991 a(1) = 1 and for n > 1, a(n) = 2 * length of the cycle reached for the map x -> A062401(x), starting at n [where A062401(n) = phi(sigma(n))], or -1 if no finite cycle is ever reached.

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

[1, 2, 2, 4, 2, 4, 4, 2, 2, 4, 4, 2, 4, 2, 2, 6, 4, 6, 2, 2, 6, 2, 2, 6, 6, 2, 6, 6, 2, 6, 6, 4, 6, 6, 6, 4, 6, 6, 6, 6, 2, 4, 2, 6, 6, 6, 6, 4, 4, 4, 6, 4, 6, 4, 6, 4, 4, 6, 6, 4, 6, 4, 4, 4, 6, 4, 4, 4, 4, 4, 6, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 6, 4, 4, 6, 4, 4, 6, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]

cp's OEIS Frontend

A082991 a(1) = 1 and for n > 1, a(n) = 2 * length of the cycle reached for the map x -> A062401(x), starting at n [where A062401(n) = phi(sigma(n))], or -1 if no finite cycle is ever reached.

Table of values

List of values

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

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

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