A073922 - cp's OEIS frontend

A073922 a(1) = 1, a(n) = smallest composite number greater than n and not occurring earlier if n is prime, or smallest prime number greater than n and not occurring earlier if n is composite.

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

[1, 4, 6, 5, 8, 7, 9, 11, 13, 17, 12, 19, 14, 23, 29, 31, 18, 37, 20, 41, 43, 47, 24, 53, 59, 61, 67, 71, 30, 73, 32, 79, 83, 89, 97, 101, 38, 103, 107, 109, 42, 113, 44, 127, 131, 137, 48, 139, 149, 151, 157, 163, 54, 167, 173, 179, 181, 191, 60, 193, 62, 197, 199]

cp's OEIS Frontend

A073922 a(1) = 1, a(n) = smallest composite number greater than n and not occurring earlier if n is prime, or smallest prime number greater than n and not occurring earlier if n is composite.

Table of values

List of values

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

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

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