A337687 - cp's OEIS frontend

A337687 a(1) = 2; for n > 1, a(n) = smallest number not occurring earlier which shares a prime factor with a(n-1) and also has a prime factor which is not a factor of a(n-1).

n	a(n)
1	2
2	6
3	10
4	12
5	14
6	18
7	15
8	20
9	22
10	24
11	21
12	28
13	26
14	30
15	33
16	36
17	34
18	38
19	40
20	35
21	42
22	39
23	45
24	48
25	44
26	46
27	50
28	52
29	54
30	51
31	57
32	60
33	55
34	65
35	70
36	58
37	56
38	62
39	66
40	63
41	69
42	72
43	68
44	74
45	76
46	78
47	75
48	80
49	82
50	84
51	77
52	88
53	86
54	90
55	85
56	95
57	100
58	92
59	94
60	96
61	87
62	93
63	99
64	102
65	98
66	91
67	104
68	106
69	108
70	105
71	110
72	112

[2, 6, 10, 12, 14, 18, 15, 20, 22, 24, 21, 28, 26, 30, 33, 36, 34, 38, 40, 35, 42, 39, 45, 48, 44, 46, 50, 52, 54, 51, 57, 60, 55, 65, 70, 58, 56, 62, 66, 63, 69, 72, 68, 74, 76, 78, 75, 80, 82, 84, 77, 88, 86, 90, 85, 95, 100, 92, 94, 96, 87, 93, 99, 102, 98, 91, 104, 106, 108, 105, 110, 112]

cp's OEIS Frontend

A337687 a(1) = 2; for n > 1, a(n) = smallest number not occurring earlier which shares a prime factor with a(n-1) and also has a prime factor which is not a factor of a(n-1).

Table of values

List of values

n	a(n)
1	2
2	6
3	10
4	12
5	14
6	18
7	15
8	20
9	22
10	24
11	21
12	28
13	26
14	30
15	33
16	36
17	34
18	38
19	40
20	35
21	42
22	39
23	45
24	48
25	44
26	46
27	50
28	52
29	54
30	51
31	57
32	60
33	55
34	65
35	70
36	58
37	56
38	62
39	66
40	63
41	69
42	72
43	68
44	74
45	76
46	78
47	75
48	80
49	82
50	84
51	77
52	88
53	86
54	90
55	85
56	95
57	100
58	92
59	94
60	96
61	87
62	93
63	99
64	102
65	98
66	91
67	104
68	106
69	108
70	105
71	110
72	112

n	a(n)
1	2
2	6
3	10
4	12
5	14
6	18
7	15
8	20
9	22
10	24
11	21
12	28
13	26
14	30
15	33
16	36
17	34
18	38
19	40
20	35
21	42
22	39
23	45
24	48
25	44
26	46
27	50
28	52
29	54
30	51
31	57
32	60
33	55
34	65
35	70
36	58
37	56
38	62
39	66
40	63
41	69
42	72
43	68
44	74
45	76
46	78
47	75
48	80
49	82
50	84
51	77
52	88
53	86
54	90
55	85
56	95
57	100
58	92
59	94
60	96
61	87
62	93
63	99
64	102
65	98
66	91
67	104
68	106
69	108
70	105
71	110
72	112

n	a(n)
1	2
2	6
3	10
4	12
5	14
6	18
7	15
8	20
9	22
10	24
11	21
12	28
13	26
14	30
15	33
16	36
17	34
18	38
19	40
20	35
21	42
22	39
23	45
24	48
25	44
26	46
27	50
28	52
29	54
30	51
31	57
32	60
33	55
34	65
35	70
36	58
37	56
38	62
39	66
40	63
41	69
42	72
43	68
44	74
45	76
46	78
47	75
48	80
49	82
50	84
51	77
52	88
53	86
54	90
55	85
56	95
57	100
58	92
59	94
60	96
61	87
62	93
63	99
64	102
65	98
66	91
67	104
68	106
69	108
70	105
71	110
72	112