A354688 - cp's OEIS frontend

A354688 a(1) = 1; for n > 1, a(n) is the smallest positive number that has not yet appeared that is coprime to a(n-1) and the difference | a(n) - a(n-1) | is distinct from all previous differences.

n	a(n)
1	1
2	2
3	5
4	3
5	7
6	12
7	19
8	4
9	13
10	21
11	8
12	25
13	6
14	17
15	11
16	23
17	9
18	29
19	39
20	10
21	31
22	15
23	37
24	14
25	41
26	16
27	47
28	65
29	18
30	53
31	20
32	57
33	83
34	22
35	61
36	27
37	55
38	79
39	24
40	67
41	26
42	71
43	33
44	73
45	43
46	75
47	119
48	30
49	89
50	32
51	81
52	28
53	93
54	35
55	86
56	149
57	34
58	101
59	45
60	91
61	127
62	36
63	107
64	38
65	111
66	49
67	97
68	139
69	40
70	117
71	167
72	42
73	121
74	46

[1, 2, 5, 3, 7, 12, 19, 4, 13, 21, 8, 25, 6, 17, 11, 23, 9, 29, 39, 10, 31, 15, 37, 14, 41, 16, 47, 65, 18, 53, 20, 57, 83, 22, 61, 27, 55, 79, 24, 67, 26, 71, 33, 73, 43, 75, 119, 30, 89, 32, 81, 28, 93, 35, 86, 149, 34, 101, 45, 91, 127, 36, 107, 38, 111, 49, 97, 139, 40, 117, 167, 42, 121, 46]

cp's OEIS Frontend

A354688 a(1) = 1; for n > 1, a(n) is the smallest positive number that has not yet appeared that is coprime to a(n-1) and the difference | a(n) - a(n-1) | is distinct from all previous differences.

Table of values

List of values

n	a(n)
1	1
2	2
3	5
4	3
5	7
6	12
7	19
8	4
9	13
10	21
11	8
12	25
13	6
14	17
15	11
16	23
17	9
18	29
19	39
20	10
21	31
22	15
23	37
24	14
25	41
26	16
27	47
28	65
29	18
30	53
31	20
32	57
33	83
34	22
35	61
36	27
37	55
38	79
39	24
40	67
41	26
42	71
43	33
44	73
45	43
46	75
47	119
48	30
49	89
50	32
51	81
52	28
53	93
54	35
55	86
56	149
57	34
58	101
59	45
60	91
61	127
62	36
63	107
64	38
65	111
66	49
67	97
68	139
69	40
70	117
71	167
72	42
73	121
74	46

n	a(n)
1	1
2	2
3	5
4	3
5	7
6	12
7	19
8	4
9	13
10	21
11	8
12	25
13	6
14	17
15	11
16	23
17	9
18	29
19	39
20	10
21	31
22	15
23	37
24	14
25	41
26	16
27	47
28	65
29	18
30	53
31	20
32	57
33	83
34	22
35	61
36	27
37	55
38	79
39	24
40	67
41	26
42	71
43	33
44	73
45	43
46	75
47	119
48	30
49	89
50	32
51	81
52	28
53	93
54	35
55	86
56	149
57	34
58	101
59	45
60	91
61	127
62	36
63	107
64	38
65	111
66	49
67	97
68	139
69	40
70	117
71	167
72	42
73	121
74	46

n	a(n)
1	1
2	2
3	5
4	3
5	7
6	12
7	19
8	4
9	13
10	21
11	8
12	25
13	6
14	17
15	11
16	23
17	9
18	29
19	39
20	10
21	31
22	15
23	37
24	14
25	41
26	16
27	47
28	65
29	18
30	53
31	20
32	57
33	83
34	22
35	61
36	27
37	55
38	79
39	24
40	67
41	26
42	71
43	33
44	73
45	43
46	75
47	119
48	30
49	89
50	32
51	81
52	28
53	93
54	35
55	86
56	149
57	34
58	101
59	45
60	91
61	127
62	36
63	107
64	38
65	111
66	49
67	97
68	139
69	40
70	117
71	167
72	42
73	121
74	46