A066724 - cp's OEIS frontend

A066724 a(1) = 1, a(2) = 2; for n > 1, a(n) is the least integer > a(n-1) such that the products a(i)*a(j) for 1 <= i < j <= n are all distinct.

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	7
7	9
8	11
9	13
10	16
11	17
12	19
13	23
14	25
15	29
16	30
17	31
18	37
19	41
20	43
21	47
22	49
23	53
24	59
25	61
26	67
27	71
28	73
29	79
30	81
31	83
32	84
33	89
34	97
35	101
36	103
37	107
38	109
39	113
40	121
41	127
42	128
43	131
44	137
45	139
46	149
47	151
48	154
49	157
50	163
51	167
52	169
53	173
54	179
55	180
56	181
57	191
58	193
59	197
60	199
61	211

[1, 2, 3, 4, 5, 7, 9, 11, 13, 16, 17, 19, 23, 25, 29, 30, 31, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 81, 83, 84, 89, 97, 101, 103, 107, 109, 113, 121, 127, 128, 131, 137, 139, 149, 151, 154, 157, 163, 167, 169, 173, 179, 180, 181, 191, 193, 197, 199, 211]

cp's OEIS Frontend

A066724 a(1) = 1, a(2) = 2; for n > 1, a(n) is the least integer > a(n-1) such that the products a(i)*a(j) for 1 <= i < j <= n are all distinct.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	7
7	9
8	11
9	13
10	16
11	17
12	19
13	23
14	25
15	29
16	30
17	31
18	37
19	41
20	43
21	47
22	49
23	53
24	59
25	61
26	67
27	71
28	73
29	79
30	81
31	83
32	84
33	89
34	97
35	101
36	103
37	107
38	109
39	113
40	121
41	127
42	128
43	131
44	137
45	139
46	149
47	151
48	154
49	157
50	163
51	167
52	169
53	173
54	179
55	180
56	181
57	191
58	193
59	197
60	199
61	211

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	7
7	9
8	11
9	13
10	16
11	17
12	19
13	23
14	25
15	29
16	30
17	31
18	37
19	41
20	43
21	47
22	49
23	53
24	59
25	61
26	67
27	71
28	73
29	79
30	81
31	83
32	84
33	89
34	97
35	101
36	103
37	107
38	109
39	113
40	121
41	127
42	128
43	131
44	137
45	139
46	149
47	151
48	154
49	157
50	163
51	167
52	169
53	173
54	179
55	180
56	181
57	191
58	193
59	197
60	199
61	211

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	7
7	9
8	11
9	13
10	16
11	17
12	19
13	23
14	25
15	29
16	30
17	31
18	37
19	41
20	43
21	47
22	49
23	53
24	59
25	61
26	67
27	71
28	73
29	79
30	81
31	83
32	84
33	89
34	97
35	101
36	103
37	107
38	109
39	113
40	121
41	127
42	128
43	131
44	137
45	139
46	149
47	151
48	154
49	157
50	163
51	167
52	169
53	173
54	179
55	180
56	181
57	191
58	193
59	197
60	199
61	211