A354749 - cp's OEIS frontend

A354749 a(1) = 1; for n > 1, a(n) is the smallest positive number greater than 1 that is coprime to a(n-1) and the product a(n) * a(n-1) is distinct from all previous products a(i) * a(i-1), i=2..n-1.

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

[1, 2, 3, 4, 5, 2, 7, 3, 5, 6, 7, 4, 9, 2, 11, 3, 8, 5, 7, 8, 9, 5, 11, 4, 13, 2, 17, 3, 13, 5, 12, 7, 9, 10, 7, 11, 6, 13, 7, 15, 8, 11, 9, 13, 8, 17, 4, 19, 2, 23, 3, 16, 5, 17, 6, 19, 3, 25, 2, 27, 4, 23, 5, 19, 7, 16, 9, 14, 11, 10, 13, 11, 12, 13, 14, 15, 11, 16, 13, 15, 16, 17, 7, 20, 9]

cp's OEIS Frontend

A354749 a(1) = 1; for n > 1, a(n) is the smallest positive number greater than 1 that is coprime to a(n-1) and the product a(n) * a(n-1) is distinct from all previous products a(i) * a(i-1), i=2..n-1.

Table of values

List of values

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

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

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