A156775 - cp's OEIS frontend

A156775 Number of iterations of x->(sigma(x)+phi(x))/2 until a non-integer or a previous term is reached, starting with x=n; a(n)=0 if this never happens.

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

[1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 3, 2, 1, 1, 1, 1, 2, 3, 2, 1, 4, 1, 3, 2, 4, 1, 3, 1, 1, 4, 3, 2, 1, 1, 4, 3, 2, 1, 9, 1, 3, 4, 2, 1, 7, 1, 1, 3, 2, 1, 8, 3, 2, 3, 2, 1, 4, 1, 8, 7, 1, 4, 3, 1, 2, 7, 6, 1, 1, 1, 4, 3, 4, 6, 5, 1, 2, 1, 2, 1, 5, 6, 5, 4, 3, 1, 9, 4, 3, 7, 6, 5, 4, 1, 1, 9, 1, 1, 5, 1, 9, 3]

cp's OEIS Frontend

A156775 Number of iterations of x->(sigma(x)+phi(x))/2 until a non-integer or a previous term is reached, starting with x=n; a(n)=0 if this never happens.

Table of values

List of values

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

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

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