A026416 - cp's OEIS frontend

A026416 A 2-way classification of integers: a(1) = 1, a(2) = 2 and for n > 2, a(n) is the smallest number not of the form a(i)*a(j) for 1 <= i < j < n.

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	24
15	25
16	29
17	30
18	31
19	37
20	40
21	41
22	42
23	43
24	47
25	49
26	53
27	54
28	56
29	59
30	61
31	66
32	67
33	70
34	71
35	73
36	78
37	79
38	81
39	83
40	88
41	89
42	97
43	101
44	102
45	103
46	104
47	105
48	107
49	109
50	110
51	113
52	114
53	121
54	127
55	128
56	130
57	131
58	135
59	136
60	137
61	138
62	139

[1, 2, 3, 4, 5, 7, 9, 11, 13, 16, 17, 19, 23, 24, 25, 29, 30, 31, 37, 40, 41, 42, 43, 47, 49, 53, 54, 56, 59, 61, 66, 67, 70, 71, 73, 78, 79, 81, 83, 88, 89, 97, 101, 102, 103, 104, 105, 107, 109, 110, 113, 114, 121, 127, 128, 130, 131, 135, 136, 137, 138, 139]

cp's OEIS Frontend

A026416 A 2-way classification of integers: a(1) = 1, a(2) = 2 and for n > 2, a(n) is the smallest number not of the form a(i)*a(j) for 1 <= i < j < n.

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	24
15	25
16	29
17	30
18	31
19	37
20	40
21	41
22	42
23	43
24	47
25	49
26	53
27	54
28	56
29	59
30	61
31	66
32	67
33	70
34	71
35	73
36	78
37	79
38	81
39	83
40	88
41	89
42	97
43	101
44	102
45	103
46	104
47	105
48	107
49	109
50	110
51	113
52	114
53	121
54	127
55	128
56	130
57	131
58	135
59	136
60	137
61	138
62	139

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	24
15	25
16	29
17	30
18	31
19	37
20	40
21	41
22	42
23	43
24	47
25	49
26	53
27	54
28	56
29	59
30	61
31	66
32	67
33	70
34	71
35	73
36	78
37	79
38	81
39	83
40	88
41	89
42	97
43	101
44	102
45	103
46	104
47	105
48	107
49	109
50	110
51	113
52	114
53	121
54	127
55	128
56	130
57	131
58	135
59	136
60	137
61	138
62	139

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	24
15	25
16	29
17	30
18	31
19	37
20	40
21	41
22	42
23	43
24	47
25	49
26	53
27	54
28	56
29	59
30	61
31	66
32	67
33	70
34	71
35	73
36	78
37	79
38	81
39	83
40	88
41	89
42	97
43	101
44	102
45	103
46	104
47	105
48	107
49	109
50	110
51	113
52	114
53	121
54	127
55	128
56	130
57	131
58	135
59	136
60	137
61	138
62	139