A272799 - cp's OEIS frontend

A272799 Numbers k such that 2k - 1 and 2k + 1 are squarefree.

n	a(n)
1	1
2	2
3	3
4	6
5	7
6	8
7	9
8	10
9	11
10	15
11	16
12	17
13	18
14	19
15	20
16	21
17	26
18	27
19	28
20	29
21	30
22	33
23	34
24	35
25	36
26	39
27	42
28	43
29	44
30	45
31	46
32	47
33	48
34	51
35	52
36	53
37	54
38	55
39	56
40	57
41	64
42	65
43	66
44	69
45	70
46	71
47	72
48	75
49	78
50	79
51	80
52	81
53	82
54	83
55	89
56	90
57	91
58	92
59	93
60	96
61	97
62	98
63	99
64	100
65	101
66	102
67	105
68	106
69	107
70	108
71	109
72	110

[1, 2, 3, 6, 7, 8, 9, 10, 11, 15, 16, 17, 18, 19, 20, 21, 26, 27, 28, 29, 30, 33, 34, 35, 36, 39, 42, 43, 44, 45, 46, 47, 48, 51, 52, 53, 54, 55, 56, 57, 64, 65, 66, 69, 70, 71, 72, 75, 78, 79, 80, 81, 82, 83, 89, 90, 91, 92, 93, 96, 97, 98, 99, 100, 101, 102, 105, 106, 107, 108, 109, 110]

cp's OEIS Frontend

A272799 Numbers k such that 2k - 1 and 2k + 1 are squarefree.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	6
5	7
6	8
7	9
8	10
9	11
10	15
11	16
12	17
13	18
14	19
15	20
16	21
17	26
18	27
19	28
20	29
21	30
22	33
23	34
24	35
25	36
26	39
27	42
28	43
29	44
30	45
31	46
32	47
33	48
34	51
35	52
36	53
37	54
38	55
39	56
40	57
41	64
42	65
43	66
44	69
45	70
46	71
47	72
48	75
49	78
50	79
51	80
52	81
53	82
54	83
55	89
56	90
57	91
58	92
59	93
60	96
61	97
62	98
63	99
64	100
65	101
66	102
67	105
68	106
69	107
70	108
71	109
72	110

n	a(n)
1	1
2	2
3	3
4	6
5	7
6	8
7	9
8	10
9	11
10	15
11	16
12	17
13	18
14	19
15	20
16	21
17	26
18	27
19	28
20	29
21	30
22	33
23	34
24	35
25	36
26	39
27	42
28	43
29	44
30	45
31	46
32	47
33	48
34	51
35	52
36	53
37	54
38	55
39	56
40	57
41	64
42	65
43	66
44	69
45	70
46	71
47	72
48	75
49	78
50	79
51	80
52	81
53	82
54	83
55	89
56	90
57	91
58	92
59	93
60	96
61	97
62	98
63	99
64	100
65	101
66	102
67	105
68	106
69	107
70	108
71	109
72	110

cp's OEIS Frontend

A272799 Numbers k such that 2*k - 1 and 2*k + 1 are squarefree.

Table of values

List of values

A272799 Numbers k such that 2k - 1 and 2k + 1 are squarefree.

n	a(n)
1	1
2	2
3	3
4	6
5	7
6	8
7	9
8	10
9	11
10	15
11	16
12	17
13	18
14	19
15	20
16	21
17	26
18	27
19	28
20	29
21	30
22	33
23	34
24	35
25	36
26	39
27	42
28	43
29	44
30	45
31	46
32	47
33	48
34	51
35	52
36	53
37	54
38	55
39	56
40	57
41	64
42	65
43	66
44	69
45	70
46	71
47	72
48	75
49	78
50	79
51	80
52	81
53	82
54	83
55	89
56	90
57	91
58	92
59	93
60	96
61	97
62	98
63	99
64	100
65	101
66	102
67	105
68	106
69	107
70	108
71	109
72	110