A172989 - cp's OEIS frontend

A172989 Smallest k such that the two numbers n^2 +- k are primes.

n	a(n)
2	1
3	2
4	3
5	6
6	5
7	12
8	3
9	2
10	3
11	18
12	5
13	12
14	3
15	2
16	15
17	18
18	7
19	12
20	21
21	2
22	63
23	42
24	55
25	6
26	15
27	10
28	27
29	12
30	19
31	78
32	15
33	2
34	93
35	12
36	5
37	78
38	15
39	10
40	21
41	12
42	23
43	18
44	57
45	14
46	27
47	30
48	7
49	120
50	117
51	8
52	15
53	42
54	37
55	24
56	27
57	58
58	93
59	18
60	7
61	12
62	75
63	38
64	3
65	6
66	7
67	132
68	27
69	28
70	69
71	18
72	5
73	102
74	27
75	34
76	75
77	78
78	5

[1, 2, 3, 6, 5, 12, 3, 2, 3, 18, 5, 12, 3, 2, 15, 18, 7, 12, 21, 2, 63, 42, 55, 6, 15, 10, 27, 12, 19, 78, 15, 2, 93, 12, 5, 78, 15, 10, 21, 12, 23, 18, 57, 14, 27, 30, 7, 120, 117, 8, 15, 42, 37, 24, 27, 58, 93, 18, 7, 12, 75, 38, 3, 6, 7, 132, 27, 28, 69, 18, 5, 102, 27, 34, 75, 78, 5]

cp's OEIS Frontend

A172989 Smallest k such that the two numbers n^2 +- k are primes.

Table of values

List of values

n	a(n)
2	1
3	2
4	3
5	6
6	5
7	12
8	3
9	2
10	3
11	18
12	5
13	12
14	3
15	2
16	15
17	18
18	7
19	12
20	21
21	2
22	63
23	42
24	55
25	6
26	15
27	10
28	27
29	12
30	19
31	78
32	15
33	2
34	93
35	12
36	5
37	78
38	15
39	10
40	21
41	12
42	23
43	18
44	57
45	14
46	27
47	30
48	7
49	120
50	117
51	8
52	15
53	42
54	37
55	24
56	27
57	58
58	93
59	18
60	7
61	12
62	75
63	38
64	3
65	6
66	7
67	132
68	27
69	28
70	69
71	18
72	5
73	102
74	27
75	34
76	75
77	78
78	5

n	a(n)
2	1
3	2
4	3
5	6
6	5
7	12
8	3
9	2
10	3
11	18
12	5
13	12
14	3
15	2
16	15
17	18
18	7
19	12
20	21
21	2
22	63
23	42
24	55
25	6
26	15
27	10
28	27
29	12
30	19
31	78
32	15
33	2
34	93
35	12
36	5
37	78
38	15
39	10
40	21
41	12
42	23
43	18
44	57
45	14
46	27
47	30
48	7
49	120
50	117
51	8
52	15
53	42
54	37
55	24
56	27
57	58
58	93
59	18
60	7
61	12
62	75
63	38
64	3
65	6
66	7
67	132
68	27
69	28
70	69
71	18
72	5
73	102
74	27
75	34
76	75
77	78
78	5

n	a(n)
2	1
3	2
4	3
5	6
6	5
7	12
8	3
9	2
10	3
11	18
12	5
13	12
14	3
15	2
16	15
17	18
18	7
19	12
20	21
21	2
22	63
23	42
24	55
25	6
26	15
27	10
28	27
29	12
30	19
31	78
32	15
33	2
34	93
35	12
36	5
37	78
38	15
39	10
40	21
41	12
42	23
43	18
44	57
45	14
46	27
47	30
48	7
49	120
50	117
51	8
52	15
53	42
54	37
55	24
56	27
57	58
58	93
59	18
60	7
61	12
62	75
63	38
64	3
65	6
66	7
67	132
68	27
69	28
70	69
71	18
72	5
73	102
74	27
75	34
76	75
77	78
78	5