A357839 - cp's OEIS frontend

A357839 a(n) is the greatest divisor > 1 of n which has already been listed, otherwise a(n) is the smallest number not yet listed; a(1) = 0.

n	a(n)
1	0
2	1
3	2
4	2
5	3
6	3
7	4
8	4
9	3
10	2
11	5
12	4
13	6
14	2
15	5
16	4
17	7
18	6
19	8
20	5
21	7
22	2
23	9
24	8
25	5
26	2
27	9
28	7
29	10
30	10
31	11
32	8
33	11
34	2
35	7
36	9
37	12
38	2
39	3
40	10
41	13
42	7
43	14
44	11
45	9
46	2
47	15
48	12
49	7
50	10
51	3
52	13
53	16
54	9
55	11
56	14
57	3
58	2
59	17
60	15
61	18
62	2
63	9
64	16
65	13
66	11
67	19
68	17
69	3
70	14
71	20
72	18
73	21
74	2
75	15
76	19
77	11

[0, 1, 2, 2, 3, 3, 4, 4, 3, 2, 5, 4, 6, 2, 5, 4, 7, 6, 8, 5, 7, 2, 9, 8, 5, 2, 9, 7, 10, 10, 11, 8, 11, 2, 7, 9, 12, 2, 3, 10, 13, 7, 14, 11, 9, 2, 15, 12, 7, 10, 3, 13, 16, 9, 11, 14, 3, 2, 17, 15, 18, 2, 9, 16, 13, 11, 19, 17, 3, 14, 20, 18, 21, 2, 15, 19, 11]

cp's OEIS Frontend

A357839 a(n) is the greatest divisor > 1 of n which has already been listed, otherwise a(n) is the smallest number not yet listed; a(1) = 0.

Table of values

List of values

n	a(n)
1	0
2	1
3	2
4	2
5	3
6	3
7	4
8	4
9	3
10	2
11	5
12	4
13	6
14	2
15	5
16	4
17	7
18	6
19	8
20	5
21	7
22	2
23	9
24	8
25	5
26	2
27	9
28	7
29	10
30	10
31	11
32	8
33	11
34	2
35	7
36	9
37	12
38	2
39	3
40	10
41	13
42	7
43	14
44	11
45	9
46	2
47	15
48	12
49	7
50	10
51	3
52	13
53	16
54	9
55	11
56	14
57	3
58	2
59	17
60	15
61	18
62	2
63	9
64	16
65	13
66	11
67	19
68	17
69	3
70	14
71	20
72	18
73	21
74	2
75	15
76	19
77	11

n	a(n)
1	0
2	1
3	2
4	2
5	3
6	3
7	4
8	4
9	3
10	2
11	5
12	4
13	6
14	2
15	5
16	4
17	7
18	6
19	8
20	5
21	7
22	2
23	9
24	8
25	5
26	2
27	9
28	7
29	10
30	10
31	11
32	8
33	11
34	2
35	7
36	9
37	12
38	2
39	3
40	10
41	13
42	7
43	14
44	11
45	9
46	2
47	15
48	12
49	7
50	10
51	3
52	13
53	16
54	9
55	11
56	14
57	3
58	2
59	17
60	15
61	18
62	2
63	9
64	16
65	13
66	11
67	19
68	17
69	3
70	14
71	20
72	18
73	21
74	2
75	15
76	19
77	11

n	a(n)
1	0
2	1
3	2
4	2
5	3
6	3
7	4
8	4
9	3
10	2
11	5
12	4
13	6
14	2
15	5
16	4
17	7
18	6
19	8
20	5
21	7
22	2
23	9
24	8
25	5
26	2
27	9
28	7
29	10
30	10
31	11
32	8
33	11
34	2
35	7
36	9
37	12
38	2
39	3
40	10
41	13
42	7
43	14
44	11
45	9
46	2
47	15
48	12
49	7
50	10
51	3
52	13
53	16
54	9
55	11
56	14
57	3
58	2
59	17
60	15
61	18
62	2
63	9
64	16
65	13
66	11
67	19
68	17
69	3
70	14
71	20
72	18
73	21
74	2
75	15
76	19
77	11