A349984 - cp's OEIS frontend

A349984 Lexicographically earliest infinite sequence of distinct positive numbers such that, for n > 2, a(n) shares a prime factor with a(n-1) that a(n-1) does not share with a(n-2).

n	a(n)
1	1
2	2
3	6
4	15
5	10
6	12
7	21
8	14
9	18
10	33
11	22
12	20
13	35
14	28
15	24
16	39
17	26
18	30
19	51
20	34
21	36
22	45
23	40
24	38
25	57
26	42
27	44
28	55
29	50
30	46
31	69
32	48
33	52
34	65
35	60
36	56
37	63
38	54
39	58
40	87
41	66
42	62
43	93
44	72
45	68
46	85
47	70
48	74
49	111
50	75
51	80
52	76
53	95
54	90
55	78
56	91
57	77
58	88
59	82
60	123
61	84
62	86
63	129
64	96
65	92
66	115
67	100
68	94
69	141
70	99
71	110
72	98

[1, 2, 6, 15, 10, 12, 21, 14, 18, 33, 22, 20, 35, 28, 24, 39, 26, 30, 51, 34, 36, 45, 40, 38, 57, 42, 44, 55, 50, 46, 69, 48, 52, 65, 60, 56, 63, 54, 58, 87, 66, 62, 93, 72, 68, 85, 70, 74, 111, 75, 80, 76, 95, 90, 78, 91, 77, 88, 82, 123, 84, 86, 129, 96, 92, 115, 100, 94, 141, 99, 110, 98]

cp's OEIS Frontend

A349984 Lexicographically earliest infinite sequence of distinct positive numbers such that, for n > 2, a(n) shares a prime factor with a(n-1) that a(n-1) does not share with a(n-2).

Table of values

List of values

n	a(n)
1	1
2	2
3	6
4	15
5	10
6	12
7	21
8	14
9	18
10	33
11	22
12	20
13	35
14	28
15	24
16	39
17	26
18	30
19	51
20	34
21	36
22	45
23	40
24	38
25	57
26	42
27	44
28	55
29	50
30	46
31	69
32	48
33	52
34	65
35	60
36	56
37	63
38	54
39	58
40	87
41	66
42	62
43	93
44	72
45	68
46	85
47	70
48	74
49	111
50	75
51	80
52	76
53	95
54	90
55	78
56	91
57	77
58	88
59	82
60	123
61	84
62	86
63	129
64	96
65	92
66	115
67	100
68	94
69	141
70	99
71	110
72	98

n	a(n)
1	1
2	2
3	6
4	15
5	10
6	12
7	21
8	14
9	18
10	33
11	22
12	20
13	35
14	28
15	24
16	39
17	26
18	30
19	51
20	34
21	36
22	45
23	40
24	38
25	57
26	42
27	44
28	55
29	50
30	46
31	69
32	48
33	52
34	65
35	60
36	56
37	63
38	54
39	58
40	87
41	66
42	62
43	93
44	72
45	68
46	85
47	70
48	74
49	111
50	75
51	80
52	76
53	95
54	90
55	78
56	91
57	77
58	88
59	82
60	123
61	84
62	86
63	129
64	96
65	92
66	115
67	100
68	94
69	141
70	99
71	110
72	98

n	a(n)
1	1
2	2
3	6
4	15
5	10
6	12
7	21
8	14
9	18
10	33
11	22
12	20
13	35
14	28
15	24
16	39
17	26
18	30
19	51
20	34
21	36
22	45
23	40
24	38
25	57
26	42
27	44
28	55
29	50
30	46
31	69
32	48
33	52
34	65
35	60
36	56
37	63
38	54
39	58
40	87
41	66
42	62
43	93
44	72
45	68
46	85
47	70
48	74
49	111
50	75
51	80
52	76
53	95
54	90
55	78
56	91
57	77
58	88
59	82
60	123
61	84
62	86
63	129
64	96
65	92
66	115
67	100
68	94
69	141
70	99
71	110
72	98