A360519 - cp's OEIS frontend

A360519 Let C consist of 1 together with all numbers with at least two distinct prime factors; this is the lexicographically earliest infinite sequence {a(n)} of distinct elements of C such that, for n>2, a(n) has a common factor with a(n-1) but not with a(n-2).

n	a(n)
1	1
2	6
3	10
4	35
5	21
6	12
7	20
8	55
9	33
10	18
11	14
12	77
13	99
14	15
15	40
16	22
17	143
18	39
19	24
20	28
21	91
22	65
23	30
24	34
25	119
26	63
27	36
28	26
29	221
30	51
31	42
32	38
33	95
34	45
35	48
36	44
37	187
38	85
39	50
40	46
41	69
42	57
43	76
44	52
45	117
46	75
47	70
48	58
49	87
50	93
51	62
52	56
53	105
54	111
55	74
56	68
57	153
58	123
59	82
60	80
61	115
62	161
63	84
64	60
65	145
66	203
67	98
68	54
69	129
70	215
71	100
72	66
73	141

[1, 6, 10, 35, 21, 12, 20, 55, 33, 18, 14, 77, 99, 15, 40, 22, 143, 39, 24, 28, 91, 65, 30, 34, 119, 63, 36, 26, 221, 51, 42, 38, 95, 45, 48, 44, 187, 85, 50, 46, 69, 57, 76, 52, 117, 75, 70, 58, 87, 93, 62, 56, 105, 111, 74, 68, 153, 123, 82, 80, 115, 161, 84, 60, 145, 203, 98, 54, 129, 215, 100, 66, 141]

cp's OEIS Frontend

A360519 Let C consist of 1 together with all numbers with at least two distinct prime factors; this is the lexicographically earliest infinite sequence {a(n)} of distinct elements of C such that, for n>2, a(n) has a common factor with a(n-1) but not with a(n-2).

Table of values

List of values

n	a(n)
1	1
2	6
3	10
4	35
5	21
6	12
7	20
8	55
9	33
10	18
11	14
12	77
13	99
14	15
15	40
16	22
17	143
18	39
19	24
20	28
21	91
22	65
23	30
24	34
25	119
26	63
27	36
28	26
29	221
30	51
31	42
32	38
33	95
34	45
35	48
36	44
37	187
38	85
39	50
40	46
41	69
42	57
43	76
44	52
45	117
46	75
47	70
48	58
49	87
50	93
51	62
52	56
53	105
54	111
55	74
56	68
57	153
58	123
59	82
60	80
61	115
62	161
63	84
64	60
65	145
66	203
67	98
68	54
69	129
70	215
71	100
72	66
73	141

n	a(n)
1	1
2	6
3	10
4	35
5	21
6	12
7	20
8	55
9	33
10	18
11	14
12	77
13	99
14	15
15	40
16	22
17	143
18	39
19	24
20	28
21	91
22	65
23	30
24	34
25	119
26	63
27	36
28	26
29	221
30	51
31	42
32	38
33	95
34	45
35	48
36	44
37	187
38	85
39	50
40	46
41	69
42	57
43	76
44	52
45	117
46	75
47	70
48	58
49	87
50	93
51	62
52	56
53	105
54	111
55	74
56	68
57	153
58	123
59	82
60	80
61	115
62	161
63	84
64	60
65	145
66	203
67	98
68	54
69	129
70	215
71	100
72	66
73	141

n	a(n)
1	1
2	6
3	10
4	35
5	21
6	12
7	20
8	55
9	33
10	18
11	14
12	77
13	99
14	15
15	40
16	22
17	143
18	39
19	24
20	28
21	91
22	65
23	30
24	34
25	119
26	63
27	36
28	26
29	221
30	51
31	42
32	38
33	95
34	45
35	48
36	44
37	187
38	85
39	50
40	46
41	69
42	57
43	76
44	52
45	117
46	75
47	70
48	58
49	87
50	93
51	62
52	56
53	105
54	111
55	74
56	68
57	153
58	123
59	82
60	80
61	115
62	161
63	84
64	60
65	145
66	203
67	98
68	54
69	129
70	215
71	100
72	66
73	141