A352187 - cp's OEIS frontend

A352187 a(1)=1, a(2)=2; thereafter, a(n) is the smallest number m not yet in the sequence such that gcd(m,a(n-1)) > 1 and gcd(m,a(n-2))=1, except that the second condition is ignored if it would imply that no choice for m were possible.

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	9
7	12
8	8
9	10
10	5
11	15
12	18
13	14
14	7
15	21
16	24
17	16
18	20
19	25
20	30
21	22
22	11
23	33
24	27
25	36
26	26
27	13
28	39
29	42
30	28
31	32
32	34
33	17
34	51
35	45
36	35
37	49
38	56
39	38
40	19
41	57
42	48
43	40
44	55
45	77
46	63
47	54
48	44
49	121
50	66
51	46
52	23
53	69
54	60
55	50
56	52
57	91
58	105
59	72
60	58
61	29
62	87
63	75
64	65
65	104
66	62
67	31
68	93
69	78
70	64
71	68
72	85
73	95
74	76
75	74
76	37
77	111
78	81
79	84
80	70
81	115
82	207
83	96
84	80

[1, 2, 4, 6, 3, 9, 12, 8, 10, 5, 15, 18, 14, 7, 21, 24, 16, 20, 25, 30, 22, 11, 33, 27, 36, 26, 13, 39, 42, 28, 32, 34, 17, 51, 45, 35, 49, 56, 38, 19, 57, 48, 40, 55, 77, 63, 54, 44, 121, 66, 46, 23, 69, 60, 50, 52, 91, 105, 72, 58, 29, 87, 75, 65, 104, 62, 31, 93, 78, 64, 68, 85, 95, 76, 74, 37, 111, 81, 84, 70, 115, 207, 96, 80]

cp's OEIS Frontend

A352187 a(1)=1, a(2)=2; thereafter, a(n) is the smallest number m not yet in the sequence such that gcd(m,a(n-1)) > 1 and gcd(m,a(n-2))=1, except that the second condition is ignored if it would imply that no choice for m were possible.

Table of values

List of values

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	9
7	12
8	8
9	10
10	5
11	15
12	18
13	14
14	7
15	21
16	24
17	16
18	20
19	25
20	30
21	22
22	11
23	33
24	27
25	36
26	26
27	13
28	39
29	42
30	28
31	32
32	34
33	17
34	51
35	45
36	35
37	49
38	56
39	38
40	19
41	57
42	48
43	40
44	55
45	77
46	63
47	54
48	44
49	121
50	66
51	46
52	23
53	69
54	60
55	50
56	52
57	91
58	105
59	72
60	58
61	29
62	87
63	75
64	65
65	104
66	62
67	31
68	93
69	78
70	64
71	68
72	85
73	95
74	76
75	74
76	37
77	111
78	81
79	84
80	70
81	115
82	207
83	96
84	80

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	9
7	12
8	8
9	10
10	5
11	15
12	18
13	14
14	7
15	21
16	24
17	16
18	20
19	25
20	30
21	22
22	11
23	33
24	27
25	36
26	26
27	13
28	39
29	42
30	28
31	32
32	34
33	17
34	51
35	45
36	35
37	49
38	56
39	38
40	19
41	57
42	48
43	40
44	55
45	77
46	63
47	54
48	44
49	121
50	66
51	46
52	23
53	69
54	60
55	50
56	52
57	91
58	105
59	72
60	58
61	29
62	87
63	75
64	65
65	104
66	62
67	31
68	93
69	78
70	64
71	68
72	85
73	95
74	76
75	74
76	37
77	111
78	81
79	84
80	70
81	115
82	207
83	96
84	80

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	9
7	12
8	8
9	10
10	5
11	15
12	18
13	14
14	7
15	21
16	24
17	16
18	20
19	25
20	30
21	22
22	11
23	33
24	27
25	36
26	26
27	13
28	39
29	42
30	28
31	32
32	34
33	17
34	51
35	45
36	35
37	49
38	56
39	38
40	19
41	57
42	48
43	40
44	55
45	77
46	63
47	54
48	44
49	121
50	66
51	46
52	23
53	69
54	60
55	50
56	52
57	91
58	105
59	72
60	58
61	29
62	87
63	75
64	65
65	104
66	62
67	31
68	93
69	78
70	64
71	68
72	85
73	95
74	76
75	74
76	37
77	111
78	81
79	84
80	70
81	115
82	207
83	96
84	80