A336363 - cp's OEIS frontend

A336363 Number of iterations of map k -> k*sigma(p^e)/p^e needed to reach a power of 2, where p is the largest prime factor of k and e is its exponent, when starting from k = n. a(n) = -1 if number of the form 2^k is never reached.

n	a(n)
1	0
2	0
3	1
4	0
5	2
6	1
7	1
8	0
9	3
10	2
11	2
12	1
13	2
14	1
15	4
16	0
17	4
18	3
19	3
20	2
21	2
22	2
23	2
24	1
25	2
26	2
27	3
28	1
29	5
30	4
31	1
32	0
33	4
34	4
35	3
36	3
37	4
38	3
39	3
40	2
41	3
42	2
43	3
44	2
45	4
46	2
47	2
48	1
49	6
50	2
51	4
52	2
53	4
54	3
55	5
56	1
57	5
58	5
59	5
60	4
61	2
62	1
63	4
64	0
65	4
66	4
67	5
68	4
69	4
70	3
71	4
72	3
73	5
74	4
75	3
76	3
77	3
78	3
79	3
80	2
81	6
82	3
83	3
84	2
85	5
86	3
87	5
88	2
89	5
90	4
91	7
92	2
93	2
94	2
95	3
96	1
97	7
98	6
99	4
100	2
101	5
102	4
103	3
104	2
105	5

[0, 0, 1, 0, 2, 1, 1, 0, 3, 2, 2, 1, 2, 1, 4, 0, 4, 3, 3, 2, 2, 2, 2, 1, 2, 2, 3, 1, 5, 4, 1, 0, 4, 4, 3, 3, 4, 3, 3, 2, 3, 2, 3, 2, 4, 2, 2, 1, 6, 2, 4, 2, 4, 3, 5, 1, 5, 5, 5, 4, 2, 1, 4, 0, 4, 4, 5, 4, 4, 3, 4, 3, 5, 4, 3, 3, 3, 3, 3, 2, 6, 3, 3, 2, 5, 3, 5, 2, 5, 4, 7, 2, 2, 2, 3, 1, 7, 6, 4, 2, 5, 4, 3, 2, 5]

cp's OEIS Frontend

A336363 Number of iterations of map k -> k*sigma(p^e)/p^e needed to reach a power of 2, where p is the largest prime factor of k and e is its exponent, when starting from k = n. a(n) = -1 if number of the form 2^k is never reached.

Table of values

List of values

n	a(n)
1	0
2	0
3	1
4	0
5	2
6	1
7	1
8	0
9	3
10	2
11	2
12	1
13	2
14	1
15	4
16	0
17	4
18	3
19	3
20	2
21	2
22	2
23	2
24	1
25	2
26	2
27	3
28	1
29	5
30	4
31	1
32	0
33	4
34	4
35	3
36	3
37	4
38	3
39	3
40	2
41	3
42	2
43	3
44	2
45	4
46	2
47	2
48	1
49	6
50	2
51	4
52	2
53	4
54	3
55	5
56	1
57	5
58	5
59	5
60	4
61	2
62	1
63	4
64	0
65	4
66	4
67	5
68	4
69	4
70	3
71	4
72	3
73	5
74	4
75	3
76	3
77	3
78	3
79	3
80	2
81	6
82	3
83	3
84	2
85	5
86	3
87	5
88	2
89	5
90	4
91	7
92	2
93	2
94	2
95	3
96	1
97	7
98	6
99	4
100	2
101	5
102	4
103	3
104	2
105	5

n	a(n)
1	0
2	0
3	1
4	0
5	2
6	1
7	1
8	0
9	3
10	2
11	2
12	1
13	2
14	1
15	4
16	0
17	4
18	3
19	3
20	2
21	2
22	2
23	2
24	1
25	2
26	2
27	3
28	1
29	5
30	4
31	1
32	0
33	4
34	4
35	3
36	3
37	4
38	3
39	3
40	2
41	3
42	2
43	3
44	2
45	4
46	2
47	2
48	1
49	6
50	2
51	4
52	2
53	4
54	3
55	5
56	1
57	5
58	5
59	5
60	4
61	2
62	1
63	4
64	0
65	4
66	4
67	5
68	4
69	4
70	3
71	4
72	3
73	5
74	4
75	3
76	3
77	3
78	3
79	3
80	2
81	6
82	3
83	3
84	2
85	5
86	3
87	5
88	2
89	5
90	4
91	7
92	2
93	2
94	2
95	3
96	1
97	7
98	6
99	4
100	2
101	5
102	4
103	3
104	2
105	5

n	a(n)
1	0
2	0
3	1
4	0
5	2
6	1
7	1
8	0
9	3
10	2
11	2
12	1
13	2
14	1
15	4
16	0
17	4
18	3
19	3
20	2
21	2
22	2
23	2
24	1
25	2
26	2
27	3
28	1
29	5
30	4
31	1
32	0
33	4
34	4
35	3
36	3
37	4
38	3
39	3
40	2
41	3
42	2
43	3
44	2
45	4
46	2
47	2
48	1
49	6
50	2
51	4
52	2
53	4
54	3
55	5
56	1
57	5
58	5
59	5
60	4
61	2
62	1
63	4
64	0
65	4
66	4
67	5
68	4
69	4
70	3
71	4
72	3
73	5
74	4
75	3
76	3
77	3
78	3
79	3
80	2
81	6
82	3
83	3
84	2
85	5
86	3
87	5
88	2
89	5
90	4
91	7
92	2
93	2
94	2
95	3
96	1
97	7
98	6
99	4
100	2
101	5
102	4
103	3
104	2
105	5