A366952 - cp's OEIS frontend

A366952 a(1) = 1, a(2) = 4; for n > 2, a(n) is the smallest positive number that has not yet appeared that shares a factor with n but does not equal n, and shares a factor with a(n-1).

n	a(n)
1	1
2	4
3	6
4	2
5	10
6	8
7	14
8	12
9	3
10	15
11	33
12	9
13	39
14	18
15	20
16	22
17	34
18	16
19	38
20	24
21	27
22	30
23	46
24	26
25	40
26	28
27	21
28	7
29	203
30	35
31	155
32	50
33	36
34	32
35	42
36	44
37	74
38	48
39	45
40	5
41	205
42	60
43	86
44	52
45	54
46	56
47	94
48	58
49	70
50	25
51	75
52	65
53	265
54	80
55	66
56	62
57	72
58	64
59	118
60	68
61	122
62	76
63	57
64	78
65	13
66	104
67	134
68	82
69	84
70	49
71	497
72	63
73	219

[1, 4, 6, 2, 10, 8, 14, 12, 3, 15, 33, 9, 39, 18, 20, 22, 34, 16, 38, 24, 27, 30, 46, 26, 40, 28, 21, 7, 203, 35, 155, 50, 36, 32, 42, 44, 74, 48, 45, 5, 205, 60, 86, 52, 54, 56, 94, 58, 70, 25, 75, 65, 265, 80, 66, 62, 72, 64, 118, 68, 122, 76, 57, 78, 13, 104, 134, 82, 84, 49, 497, 63, 219]

cp's OEIS Frontend

A366952 a(1) = 1, a(2) = 4; for n > 2, a(n) is the smallest positive number that has not yet appeared that shares a factor with n but does not equal n, and shares a factor with a(n-1).

Table of values

List of values

n	a(n)
1	1
2	4
3	6
4	2
5	10
6	8
7	14
8	12
9	3
10	15
11	33
12	9
13	39
14	18
15	20
16	22
17	34
18	16
19	38
20	24
21	27
22	30
23	46
24	26
25	40
26	28
27	21
28	7
29	203
30	35
31	155
32	50
33	36
34	32
35	42
36	44
37	74
38	48
39	45
40	5
41	205
42	60
43	86
44	52
45	54
46	56
47	94
48	58
49	70
50	25
51	75
52	65
53	265
54	80
55	66
56	62
57	72
58	64
59	118
60	68
61	122
62	76
63	57
64	78
65	13
66	104
67	134
68	82
69	84
70	49
71	497
72	63
73	219

n	a(n)
1	1
2	4
3	6
4	2
5	10
6	8
7	14
8	12
9	3
10	15
11	33
12	9
13	39
14	18
15	20
16	22
17	34
18	16
19	38
20	24
21	27
22	30
23	46
24	26
25	40
26	28
27	21
28	7
29	203
30	35
31	155
32	50
33	36
34	32
35	42
36	44
37	74
38	48
39	45
40	5
41	205
42	60
43	86
44	52
45	54
46	56
47	94
48	58
49	70
50	25
51	75
52	65
53	265
54	80
55	66
56	62
57	72
58	64
59	118
60	68
61	122
62	76
63	57
64	78
65	13
66	104
67	134
68	82
69	84
70	49
71	497
72	63
73	219

n	a(n)
1	1
2	4
3	6
4	2
5	10
6	8
7	14
8	12
9	3
10	15
11	33
12	9
13	39
14	18
15	20
16	22
17	34
18	16
19	38
20	24
21	27
22	30
23	46
24	26
25	40
26	28
27	21
28	7
29	203
30	35
31	155
32	50
33	36
34	32
35	42
36	44
37	74
38	48
39	45
40	5
41	205
42	60
43	86
44	52
45	54
46	56
47	94
48	58
49	70
50	25
51	75
52	65
53	265
54	80
55	66
56	62
57	72
58	64
59	118
60	68
61	122
62	76
63	57
64	78
65	13
66	104
67	134
68	82
69	84
70	49
71	497
72	63
73	219