A362071 - cp's OEIS frontend

A362071 a(1) = 1, and thereafter a(n) is the number of terms with index m < n such that gpf(a(m)) = gpf(a(n-1)), where gpf(k) = A006530(k) is the greatest prime factor of k (or 1 if k=1).

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

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

cp's OEIS Frontend

A362071 a(1) = 1, and thereafter a(n) is the number of terms with index m < n such that gpf(a(m)) = gpf(a(n-1)), where gpf(k) = A006530(k) is the greatest prime factor of k (or 1 if k=1).

Table of values

List of values

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

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

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