A236675 - cp's OEIS frontend

A236675 If n is prime, then a(n) is the least composite number not occurring earlier, else a(n) is the least prime not occurring earlier.

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

[2, 4, 6, 3, 8, 5, 9, 7, 11, 13, 10, 17, 12, 19, 23, 29, 14, 31, 15, 37, 41, 43, 16, 47, 53, 59, 61, 67, 18, 71, 20, 73, 79, 83, 89, 97, 21, 101, 103, 107, 22, 109, 24, 113, 127, 131, 25, 137, 139, 149, 151, 157, 26, 163, 167, 173, 179, 181, 27, 191, 28, 193]

cp's OEIS Frontend

A236675 If n is prime, then a(n) is the least composite number not occurring earlier, else a(n) is the least prime not occurring earlier.

Table of values

List of values

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

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

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