A005528 - cp's OEIS frontend

A005528 Størmer numbers or arc-cotangent irreducible numbers: numbers k such that the largest prime factor of k^2 + 1 is >= 2*k.

n	a(n)
1	1
2	2
3	4
4	5
5	6
6	9
7	10
8	11
9	12
10	14
11	15
12	16
13	19
14	20
15	22
16	23
17	24
18	25
19	26
20	27
21	28
22	29
23	33
24	34
25	35
26	36
27	37
28	39
29	40
30	42
31	44
32	45
33	48
34	49
35	51
36	52
37	53
38	54
39	56
40	58
41	59
42	60
43	61
44	62
45	63
46	64
47	65
48	66
49	67
50	69
51	71
52	74
53	77
54	78
55	79
56	80
57	81
58	82
59	84
60	85
61	86
62	87
63	88
64	89
65	90
66	92
67	94
68	95
69	96

[1, 2, 4, 5, 6, 9, 10, 11, 12, 14, 15, 16, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 33, 34, 35, 36, 37, 39, 40, 42, 44, 45, 48, 49, 51, 52, 53, 54, 56, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 69, 71, 74, 77, 78, 79, 80, 81, 82, 84, 85, 86, 87, 88, 89, 90, 92, 94, 95, 96]

cp's OEIS Frontend

A005528 Størmer numbers or arc-cotangent irreducible numbers: numbers k such that the largest prime factor of k^2 + 1 is >= 2*k.

Table of values

List of values

n	a(n)
1	1
2	2
3	4
4	5
5	6
6	9
7	10
8	11
9	12
10	14
11	15
12	16
13	19
14	20
15	22
16	23
17	24
18	25
19	26
20	27
21	28
22	29
23	33
24	34
25	35
26	36
27	37
28	39
29	40
30	42
31	44
32	45
33	48
34	49
35	51
36	52
37	53
38	54
39	56
40	58
41	59
42	60
43	61
44	62
45	63
46	64
47	65
48	66
49	67
50	69
51	71
52	74
53	77
54	78
55	79
56	80
57	81
58	82
59	84
60	85
61	86
62	87
63	88
64	89
65	90
66	92
67	94
68	95
69	96

n	a(n)
1	1
2	2
3	4
4	5
5	6
6	9
7	10
8	11
9	12
10	14
11	15
12	16
13	19
14	20
15	22
16	23
17	24
18	25
19	26
20	27
21	28
22	29
23	33
24	34
25	35
26	36
27	37
28	39
29	40
30	42
31	44
32	45
33	48
34	49
35	51
36	52
37	53
38	54
39	56
40	58
41	59
42	60
43	61
44	62
45	63
46	64
47	65
48	66
49	67
50	69
51	71
52	74
53	77
54	78
55	79
56	80
57	81
58	82
59	84
60	85
61	86
62	87
63	88
64	89
65	90
66	92
67	94
68	95
69	96

n	a(n)
1	1
2	2
3	4
4	5
5	6
6	9
7	10
8	11
9	12
10	14
11	15
12	16
13	19
14	20
15	22
16	23
17	24
18	25
19	26
20	27
21	28
22	29
23	33
24	34
25	35
26	36
27	37
28	39
29	40
30	42
31	44
32	45
33	48
34	49
35	51
36	52
37	53
38	54
39	56
40	58
41	59
42	60
43	61
44	62
45	63
46	64
47	65
48	66
49	67
50	69
51	71
52	74
53	77
54	78
55	79
56	80
57	81
58	82
59	84
60	85
61	86
62	87
63	88
64	89
65	90
66	92
67	94
68	95
69	96