A090252 - cp's OEIS frontend

A090252 The Two-Up sequence: a(n) is the least positive number not already used that is coprime to the previous floor(n/2) terms.

n	a(n)
1	1
2	2
3	3
4	5
5	4
6	7
7	9
8	11
9	13
10	17
11	8
12	19
13	23
14	25
15	21
16	29
17	31
18	37
19	41
20	43
21	47
22	53
23	16
24	59
25	61
26	67
27	71
28	73
29	55
30	79
31	27
32	49
33	83
34	89
35	97
36	101
37	103
38	107
39	109
40	113
41	127
42	131
43	137
44	139
45	149
46	151
47	26
48	157
49	163
50	167
51	173
52	179
53	181
54	191
55	193
56	197
57	199
58	211
59	85
60	121
61	223
62	227
63	57
64	229

[1, 2, 3, 5, 4, 7, 9, 11, 13, 17, 8, 19, 23, 25, 21, 29, 31, 37, 41, 43, 47, 53, 16, 59, 61, 67, 71, 73, 55, 79, 27, 49, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 26, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 85, 121, 223, 227, 57, 229]

cp's OEIS Frontend

A090252 The Two-Up sequence: a(n) is the least positive number not already used that is coprime to the previous floor(n/2) terms.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	5
5	4
6	7
7	9
8	11
9	13
10	17
11	8
12	19
13	23
14	25
15	21
16	29
17	31
18	37
19	41
20	43
21	47
22	53
23	16
24	59
25	61
26	67
27	71
28	73
29	55
30	79
31	27
32	49
33	83
34	89
35	97
36	101
37	103
38	107
39	109
40	113
41	127
42	131
43	137
44	139
45	149
46	151
47	26
48	157
49	163
50	167
51	173
52	179
53	181
54	191
55	193
56	197
57	199
58	211
59	85
60	121
61	223
62	227
63	57
64	229

n	a(n)
1	1
2	2
3	3
4	5
5	4
6	7
7	9
8	11
9	13
10	17
11	8
12	19
13	23
14	25
15	21
16	29
17	31
18	37
19	41
20	43
21	47
22	53
23	16
24	59
25	61
26	67
27	71
28	73
29	55
30	79
31	27
32	49
33	83
34	89
35	97
36	101
37	103
38	107
39	109
40	113
41	127
42	131
43	137
44	139
45	149
46	151
47	26
48	157
49	163
50	167
51	173
52	179
53	181
54	191
55	193
56	197
57	199
58	211
59	85
60	121
61	223
62	227
63	57
64	229

n	a(n)
1	1
2	2
3	3
4	5
5	4
6	7
7	9
8	11
9	13
10	17
11	8
12	19
13	23
14	25
15	21
16	29
17	31
18	37
19	41
20	43
21	47
22	53
23	16
24	59
25	61
26	67
27	71
28	73
29	55
30	79
31	27
32	49
33	83
34	89
35	97
36	101
37	103
38	107
39	109
40	113
41	127
42	131
43	137
44	139
45	149
46	151
47	26
48	157
49	163
50	167
51	173
52	179
53	181
54	191
55	193
56	197
57	199
58	211
59	85
60	121
61	223
62	227
63	57
64	229