A349491 - cp's OEIS frontend

A349491 a(1)=1, a(2)=4; for n > 2, a(n) is the smallest unused positive number such that gcd(a(n-1)*n,a(n)) > 1, where a(n) != a(n-1) and a(n) != n.

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

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

cp's OEIS Frontend

A349491 a(1)=1, a(2)=4; for n > 2, a(n) is the smallest unused positive number such that gcd(a(n-1)*n,a(n)) > 1, where a(n) != a(n-1) and a(n) != n.

Table of values

List of values

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

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

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