A330877 - cp's OEIS frontend

A330877 Number of steps needed to reach zero or a cycle when starting from k = n and repeatedly applying the map that replaces k by k - d(k) if k is even, by k + d(k) if k is odd, where d(k) is the number of divisors of k (A000005).

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

[0, 2, 1, 7, 3, 6, 2, 5, 4, 4, 3, 12, 3, 11, 4, 10, 13, 10, 4, 9, 5, 8, 5, 8, 14, 7, 6, 32, 6, 32, 6, 31, 7, 30, 7, 29, 33, 29, 8, 28, 8, 28, 8, 27, 9, 26, 9, 12, 9, 11, 10, 25, 10, 25, 10, 24, 10, 23, 11, 23, 10, 22, 12, 21, 24, 21, 12, 21, 13]

cp's OEIS Frontend

A330877 Number of steps needed to reach zero or a cycle when starting from k = n and repeatedly applying the map that replaces k by k - d(k) if k is even, by k + d(k) if k is odd, where d(k) is the number of divisors of k (A000005).

Table of values

List of values

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

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

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