A075075 - cp's OEIS frontend

A075075 a(1) = 1, a(2) = 2 and then the smallest number not occurring earlier such that every term divides the product of its neighbors: a(n-1)*a(n+1)/a(n) is an integer.

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	5
7	10
8	8
9	12
10	9
11	15
12	20
13	16
14	24
15	18
16	21
17	7
18	11
19	22
20	14
21	28
22	26
23	13
24	17
25	34
26	30
27	45
28	27
29	33
30	44
31	32
32	40
33	25
34	35
35	42
36	36
37	48
38	52
39	39
40	51
41	68
42	56
43	70
44	50
45	55
46	66
47	54
48	63
49	49
50	77
51	88
52	64
53	72
54	81
55	90
56	60
57	38
58	19
59	23
60	46
61	58
62	29
63	31
64	62
65	74
66	37
67	41
68	82
69	76
70	114
71	57
72	43

[1, 2, 4, 6, 3, 5, 10, 8, 12, 9, 15, 20, 16, 24, 18, 21, 7, 11, 22, 14, 28, 26, 13, 17, 34, 30, 45, 27, 33, 44, 32, 40, 25, 35, 42, 36, 48, 52, 39, 51, 68, 56, 70, 50, 55, 66, 54, 63, 49, 77, 88, 64, 72, 81, 90, 60, 38, 19, 23, 46, 58, 29, 31, 62, 74, 37, 41, 82, 76, 114, 57, 43]

cp's OEIS Frontend

A075075 a(1) = 1, a(2) = 2 and then the smallest number not occurring earlier such that every term divides the product of its neighbors: a(n-1)*a(n+1)/a(n) is an integer.

Table of values

List of values

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	5
7	10
8	8
9	12
10	9
11	15
12	20
13	16
14	24
15	18
16	21
17	7
18	11
19	22
20	14
21	28
22	26
23	13
24	17
25	34
26	30
27	45
28	27
29	33
30	44
31	32
32	40
33	25
34	35
35	42
36	36
37	48
38	52
39	39
40	51
41	68
42	56
43	70
44	50
45	55
46	66
47	54
48	63
49	49
50	77
51	88
52	64
53	72
54	81
55	90
56	60
57	38
58	19
59	23
60	46
61	58
62	29
63	31
64	62
65	74
66	37
67	41
68	82
69	76
70	114
71	57
72	43

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	5
7	10
8	8
9	12
10	9
11	15
12	20
13	16
14	24
15	18
16	21
17	7
18	11
19	22
20	14
21	28
22	26
23	13
24	17
25	34
26	30
27	45
28	27
29	33
30	44
31	32
32	40
33	25
34	35
35	42
36	36
37	48
38	52
39	39
40	51
41	68
42	56
43	70
44	50
45	55
46	66
47	54
48	63
49	49
50	77
51	88
52	64
53	72
54	81
55	90
56	60
57	38
58	19
59	23
60	46
61	58
62	29
63	31
64	62
65	74
66	37
67	41
68	82
69	76
70	114
71	57
72	43

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	5
7	10
8	8
9	12
10	9
11	15
12	20
13	16
14	24
15	18
16	21
17	7
18	11
19	22
20	14
21	28
22	26
23	13
24	17
25	34
26	30
27	45
28	27
29	33
30	44
31	32
32	40
33	25
34	35
35	42
36	36
37	48
38	52
39	39
40	51
41	68
42	56
43	70
44	50
45	55
46	66
47	54
48	63
49	49
50	77
51	88
52	64
53	72
54	81
55	90
56	60
57	38
58	19
59	23
60	46
61	58
62	29
63	31
64	62
65	74
66	37
67	41
68	82
69	76
70	114
71	57
72	43