A356903 - cp's OEIS frontend

A356903 a(1) = 1, a(2) = 2; for n > 2, a(n) is the smallest positive number not occurring earlier such that a(n) is coprime to the previous tau(a(n)) terms.

n	a(n)
1	1
2	2
3	3
4	5
5	7
6	4
7	9
8	11
9	13
10	17
11	8
12	15
13	19
14	23
15	29
16	14
17	25
18	27
19	31
20	37
21	22
22	35
23	39
24	41
25	43
26	34
27	47
28	21
29	53
30	55
31	26
32	49
33	51
34	59
35	61
36	10
37	67
38	33
39	71
40	73
41	38
42	65
43	69
44	77
45	79
46	58
47	83
48	57
49	85
50	89
51	46
52	91
53	87
54	95
55	97
56	62
57	101
58	103
59	81
60	107
61	74
62	109
63	113
64	93
65	115
66	82
67	119
68	121
69	111
70	125
71	86
72	127
73	131
74	123

[1, 2, 3, 5, 7, 4, 9, 11, 13, 17, 8, 15, 19, 23, 29, 14, 25, 27, 31, 37, 22, 35, 39, 41, 43, 34, 47, 21, 53, 55, 26, 49, 51, 59, 61, 10, 67, 33, 71, 73, 38, 65, 69, 77, 79, 58, 83, 57, 85, 89, 46, 91, 87, 95, 97, 62, 101, 103, 81, 107, 74, 109, 113, 93, 115, 82, 119, 121, 111, 125, 86, 127, 131, 123]

cp's OEIS Frontend

A356903 a(1) = 1, a(2) = 2; for n > 2, a(n) is the smallest positive number not occurring earlier such that a(n) is coprime to the previous tau(a(n)) terms.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	5
5	7
6	4
7	9
8	11
9	13
10	17
11	8
12	15
13	19
14	23
15	29
16	14
17	25
18	27
19	31
20	37
21	22
22	35
23	39
24	41
25	43
26	34
27	47
28	21
29	53
30	55
31	26
32	49
33	51
34	59
35	61
36	10
37	67
38	33
39	71
40	73
41	38
42	65
43	69
44	77
45	79
46	58
47	83
48	57
49	85
50	89
51	46
52	91
53	87
54	95
55	97
56	62
57	101
58	103
59	81
60	107
61	74
62	109
63	113
64	93
65	115
66	82
67	119
68	121
69	111
70	125
71	86
72	127
73	131
74	123

n	a(n)
1	1
2	2
3	3
4	5
5	7
6	4
7	9
8	11
9	13
10	17
11	8
12	15
13	19
14	23
15	29
16	14
17	25
18	27
19	31
20	37
21	22
22	35
23	39
24	41
25	43
26	34
27	47
28	21
29	53
30	55
31	26
32	49
33	51
34	59
35	61
36	10
37	67
38	33
39	71
40	73
41	38
42	65
43	69
44	77
45	79
46	58
47	83
48	57
49	85
50	89
51	46
52	91
53	87
54	95
55	97
56	62
57	101
58	103
59	81
60	107
61	74
62	109
63	113
64	93
65	115
66	82
67	119
68	121
69	111
70	125
71	86
72	127
73	131
74	123

n	a(n)
1	1
2	2
3	3
4	5
5	7
6	4
7	9
8	11
9	13
10	17
11	8
12	15
13	19
14	23
15	29
16	14
17	25
18	27
19	31
20	37
21	22
22	35
23	39
24	41
25	43
26	34
27	47
28	21
29	53
30	55
31	26
32	49
33	51
34	59
35	61
36	10
37	67
38	33
39	71
40	73
41	38
42	65
43	69
44	77
45	79
46	58
47	83
48	57
49	85
50	89
51	46
52	91
53	87
54	95
55	97
56	62
57	101
58	103
59	81
60	107
61	74
62	109
63	113
64	93
65	115
66	82
67	119
68	121
69	111
70	125
71	86
72	127
73	131
74	123