A263650 - cp's OEIS frontend

A263650 A variation on A098550 (the Yellowstone permutation): a(n)=n for 1 <= n <= 3, a(4)=5; otherwise a(n) = smallest number not yet appearing in the sequence which is coprime to a(n-1) and not coprime to a(n-2).

n	a(n)
1	1
2	2
3	3
4	5
5	6
6	25
7	4
8	15
9	8
10	9
11	10
12	21
13	16
14	7
15	12
16	35
17	18
18	49
19	20
20	63
21	22
22	27
23	11
24	24
25	55
26	14
27	33
28	26
29	45
30	13
31	30
32	91
33	32
34	39
35	28
36	51
37	38
38	17
39	19
40	34
41	57
42	40
43	69
44	44
45	23
46	36
47	115
48	42
49	65
50	46
51	75
52	52
53	81
54	50
55	87
56	56
57	29
58	48
59	145
60	54
61	85
62	58
63	95
64	62
65	105
66	31
67	60
68	217
69	64

[1, 2, 3, 5, 6, 25, 4, 15, 8, 9, 10, 21, 16, 7, 12, 35, 18, 49, 20, 63, 22, 27, 11, 24, 55, 14, 33, 26, 45, 13, 30, 91, 32, 39, 28, 51, 38, 17, 19, 34, 57, 40, 69, 44, 23, 36, 115, 42, 65, 46, 75, 52, 81, 50, 87, 56, 29, 48, 145, 54, 85, 58, 95, 62, 105, 31, 60, 217, 64]

cp's OEIS Frontend

A263650 A variation on A098550 (the Yellowstone permutation): a(n)=n for 1 <= n <= 3, a(4)=5; otherwise a(n) = smallest number not yet appearing in the sequence which is coprime to a(n-1) and not coprime to a(n-2).

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	5
5	6
6	25
7	4
8	15
9	8
10	9
11	10
12	21
13	16
14	7
15	12
16	35
17	18
18	49
19	20
20	63
21	22
22	27
23	11
24	24
25	55
26	14
27	33
28	26
29	45
30	13
31	30
32	91
33	32
34	39
35	28
36	51
37	38
38	17
39	19
40	34
41	57
42	40
43	69
44	44
45	23
46	36
47	115
48	42
49	65
50	46
51	75
52	52
53	81
54	50
55	87
56	56
57	29
58	48
59	145
60	54
61	85
62	58
63	95
64	62
65	105
66	31
67	60
68	217
69	64

n	a(n)
1	1
2	2
3	3
4	5
5	6
6	25
7	4
8	15
9	8
10	9
11	10
12	21
13	16
14	7
15	12
16	35
17	18
18	49
19	20
20	63
21	22
22	27
23	11
24	24
25	55
26	14
27	33
28	26
29	45
30	13
31	30
32	91
33	32
34	39
35	28
36	51
37	38
38	17
39	19
40	34
41	57
42	40
43	69
44	44
45	23
46	36
47	115
48	42
49	65
50	46
51	75
52	52
53	81
54	50
55	87
56	56
57	29
58	48
59	145
60	54
61	85
62	58
63	95
64	62
65	105
66	31
67	60
68	217
69	64

n	a(n)
1	1
2	2
3	3
4	5
5	6
6	25
7	4
8	15
9	8
10	9
11	10
12	21
13	16
14	7
15	12
16	35
17	18
18	49
19	20
20	63
21	22
22	27
23	11
24	24
25	55
26	14
27	33
28	26
29	45
30	13
31	30
32	91
33	32
34	39
35	28
36	51
37	38
38	17
39	19
40	34
41	57
42	40
43	69
44	44
45	23
46	36
47	115
48	42
49	65
50	46
51	75
52	52
53	81
54	50
55	87
56	56
57	29
58	48
59	145
60	54
61	85
62	58
63	95
64	62
65	105
66	31
67	60
68	217
69	64