A352097 - cp's OEIS frontend

A352097 a(1) = 4, a(2) = 9; let i = a(n-2) and j = a(n-1); a(n) = least k not already in the sequence such that gcd(j, k) = 1 and 1 < gcd(i, k) != i != k.

n	a(n)
1	4
2	9
3	10
4	21
5	8
6	15
7	14
8	25
9	6
10	35
11	16
12	45
13	22
14	27
15	20
16	33
17	26
18	51
19	28
20	39
21	32
22	57
23	34
24	63
25	38
26	49
27	12
28	77
29	18
30	55
31	24
32	65
33	36
34	85
35	42
36	95
37	44
38	75
39	46
40	81
41	40
42	69
43	50
44	87
45	52
46	93
47	56
48	99
49	58
50	105
51	62
52	91
53	30
54	119
55	48
56	133
57	54
58	161
59	60
60	203
61	64
62	145
63	66
64	115
65	68

[4, 9, 10, 21, 8, 15, 14, 25, 6, 35, 16, 45, 22, 27, 20, 33, 26, 51, 28, 39, 32, 57, 34, 63, 38, 49, 12, 77, 18, 55, 24, 65, 36, 85, 42, 95, 44, 75, 46, 81, 40, 69, 50, 87, 52, 93, 56, 99, 58, 105, 62, 91, 30, 119, 48, 133, 54, 161, 60, 203, 64, 145, 66, 115, 68]

cp's OEIS Frontend

A352097 a(1) = 4, a(2) = 9; let i = a(n-2) and j = a(n-1); a(n) = least k not already in the sequence such that gcd(j, k) = 1 and 1 < gcd(i, k) != i != k.

Table of values

List of values

n	a(n)
1	4
2	9
3	10
4	21
5	8
6	15
7	14
8	25
9	6
10	35
11	16
12	45
13	22
14	27
15	20
16	33
17	26
18	51
19	28
20	39
21	32
22	57
23	34
24	63
25	38
26	49
27	12
28	77
29	18
30	55
31	24
32	65
33	36
34	85
35	42
36	95
37	44
38	75
39	46
40	81
41	40
42	69
43	50
44	87
45	52
46	93
47	56
48	99
49	58
50	105
51	62
52	91
53	30
54	119
55	48
56	133
57	54
58	161
59	60
60	203
61	64
62	145
63	66
64	115
65	68

n	a(n)
1	4
2	9
3	10
4	21
5	8
6	15
7	14
8	25
9	6
10	35
11	16
12	45
13	22
14	27
15	20
16	33
17	26
18	51
19	28
20	39
21	32
22	57
23	34
24	63
25	38
26	49
27	12
28	77
29	18
30	55
31	24
32	65
33	36
34	85
35	42
36	95
37	44
38	75
39	46
40	81
41	40
42	69
43	50
44	87
45	52
46	93
47	56
48	99
49	58
50	105
51	62
52	91
53	30
54	119
55	48
56	133
57	54
58	161
59	60
60	203
61	64
62	145
63	66
64	115
65	68

n	a(n)
1	4
2	9
3	10
4	21
5	8
6	15
7	14
8	25
9	6
10	35
11	16
12	45
13	22
14	27
15	20
16	33
17	26
18	51
19	28
20	39
21	32
22	57
23	34
24	63
25	38
26	49
27	12
28	77
29	18
30	55
31	24
32	65
33	36
34	85
35	42
36	95
37	44
38	75
39	46
40	81
41	40
42	69
43	50
44	87
45	52
46	93
47	56
48	99
49	58
50	105
51	62
52	91
53	30
54	119
55	48
56	133
57	54
58	161
59	60
60	203
61	64
62	145
63	66
64	115
65	68