A375719 - cp's OEIS frontend

A375719 a(1) = 1; For n > 1, a(n) is the smallest number different from a(1), ..., a(n-1) such that lcm(a(1), ..., a(n)) is a perfect square.

n	a(n)
1	1
2	4
3	2
4	9
5	3
6	6
7	12
8	16
9	8
10	18
11	24
12	25
13	5
14	10
15	15
16	20
17	30
18	36
19	40
20	45
21	48
22	49
23	7
24	14
25	21
26	28
27	35
28	42
29	50
30	56
31	60
32	63
33	64
34	32
35	70
36	72
37	75
38	80
39	81
40	27
41	54
42	84
43	90
44	96
45	98
46	100
47	105
48	108
49	112
50	120
51	121
52	11
53	22
54	33
55	44
56	55
57	66
58	77
59	88
60	99
61	110
62	126
63	132
64	135
65	140

[1, 4, 2, 9, 3, 6, 12, 16, 8, 18, 24, 25, 5, 10, 15, 20, 30, 36, 40, 45, 48, 49, 7, 14, 21, 28, 35, 42, 50, 56, 60, 63, 64, 32, 70, 72, 75, 80, 81, 27, 54, 84, 90, 96, 98, 100, 105, 108, 112, 120, 121, 11, 22, 33, 44, 55, 66, 77, 88, 99, 110, 126, 132, 135, 140]

cp's OEIS Frontend

A375719 a(1) = 1; For n > 1, a(n) is the smallest number different from a(1), ..., a(n-1) such that lcm(a(1), ..., a(n)) is a perfect square.

Table of values

List of values

n	a(n)
1	1
2	4
3	2
4	9
5	3
6	6
7	12
8	16
9	8
10	18
11	24
12	25
13	5
14	10
15	15
16	20
17	30
18	36
19	40
20	45
21	48
22	49
23	7
24	14
25	21
26	28
27	35
28	42
29	50
30	56
31	60
32	63
33	64
34	32
35	70
36	72
37	75
38	80
39	81
40	27
41	54
42	84
43	90
44	96
45	98
46	100
47	105
48	108
49	112
50	120
51	121
52	11
53	22
54	33
55	44
56	55
57	66
58	77
59	88
60	99
61	110
62	126
63	132
64	135
65	140

n	a(n)
1	1
2	4
3	2
4	9
5	3
6	6
7	12
8	16
9	8
10	18
11	24
12	25
13	5
14	10
15	15
16	20
17	30
18	36
19	40
20	45
21	48
22	49
23	7
24	14
25	21
26	28
27	35
28	42
29	50
30	56
31	60
32	63
33	64
34	32
35	70
36	72
37	75
38	80
39	81
40	27
41	54
42	84
43	90
44	96
45	98
46	100
47	105
48	108
49	112
50	120
51	121
52	11
53	22
54	33
55	44
56	55
57	66
58	77
59	88
60	99
61	110
62	126
63	132
64	135
65	140

n	a(n)
1	1
2	4
3	2
4	9
5	3
6	6
7	12
8	16
9	8
10	18
11	24
12	25
13	5
14	10
15	15
16	20
17	30
18	36
19	40
20	45
21	48
22	49
23	7
24	14
25	21
26	28
27	35
28	42
29	50
30	56
31	60
32	63
33	64
34	32
35	70
36	72
37	75
38	80
39	81
40	27
41	54
42	84
43	90
44	96
45	98
46	100
47	105
48	108
49	112
50	120
51	121
52	11
53	22
54	33
55	44
56	55
57	66
58	77
59	88
60	99
61	110
62	126
63	132
64	135
65	140