A120224 - cp's OEIS frontend

A120224 a(n) is the minimal number k>=n such that n+k and n*k+1 are primes.

n	a(n)
1	1
2	3
3	4
4	7
5	6
6	7
7	10
8	9
9	14
10	13
11	18
12	19
13	24
14	15
15	16
16	21
17	24
18	29
19	22
20	21
21	22
22	31
23	30
24	43
25	28
26	33
27	34
28	39
29	32
30	41
31	36
32	39
33	34
34	37
35	66
36	43
37	60
38	41
39	50
40	43
41	42
42	55
43	46
44	53
45	52
46	51
47	50
48	59
49	52
50	51
51	56
52	55
53	56
54	55
55	58
56	75
57	74
58	69
59	68
60	67
61	66
62	75
63	74
64	67
65	86
66	83
67	70
68	89
69	70
70	79
71	102
72	79

[1, 3, 4, 7, 6, 7, 10, 9, 14, 13, 18, 19, 24, 15, 16, 21, 24, 29, 22, 21, 22, 31, 30, 43, 28, 33, 34, 39, 32, 41, 36, 39, 34, 37, 66, 43, 60, 41, 50, 43, 42, 55, 46, 53, 52, 51, 50, 59, 52, 51, 56, 55, 56, 55, 58, 75, 74, 69, 68, 67, 66, 75, 74, 67, 86, 83, 70, 89, 70, 79, 102, 79]

cp's OEIS Frontend

A120224 a(n) is the minimal number k>=n such that n+k and n*k+1 are primes.

Table of values

List of values

n	a(n)
1	1
2	3
3	4
4	7
5	6
6	7
7	10
8	9
9	14
10	13
11	18
12	19
13	24
14	15
15	16
16	21
17	24
18	29
19	22
20	21
21	22
22	31
23	30
24	43
25	28
26	33
27	34
28	39
29	32
30	41
31	36
32	39
33	34
34	37
35	66
36	43
37	60
38	41
39	50
40	43
41	42
42	55
43	46
44	53
45	52
46	51
47	50
48	59
49	52
50	51
51	56
52	55
53	56
54	55
55	58
56	75
57	74
58	69
59	68
60	67
61	66
62	75
63	74
64	67
65	86
66	83
67	70
68	89
69	70
70	79
71	102
72	79

n	a(n)
1	1
2	3
3	4
4	7
5	6
6	7
7	10
8	9
9	14
10	13
11	18
12	19
13	24
14	15
15	16
16	21
17	24
18	29
19	22
20	21
21	22
22	31
23	30
24	43
25	28
26	33
27	34
28	39
29	32
30	41
31	36
32	39
33	34
34	37
35	66
36	43
37	60
38	41
39	50
40	43
41	42
42	55
43	46
44	53
45	52
46	51
47	50
48	59
49	52
50	51
51	56
52	55
53	56
54	55
55	58
56	75
57	74
58	69
59	68
60	67
61	66
62	75
63	74
64	67
65	86
66	83
67	70
68	89
69	70
70	79
71	102
72	79

n	a(n)
1	1
2	3
3	4
4	7
5	6
6	7
7	10
8	9
9	14
10	13
11	18
12	19
13	24
14	15
15	16
16	21
17	24
18	29
19	22
20	21
21	22
22	31
23	30
24	43
25	28
26	33
27	34
28	39
29	32
30	41
31	36
32	39
33	34
34	37
35	66
36	43
37	60
38	41
39	50
40	43
41	42
42	55
43	46
44	53
45	52
46	51
47	50
48	59
49	52
50	51
51	56
52	55
53	56
54	55
55	58
56	75
57	74
58	69
59	68
60	67
61	66
62	75
63	74
64	67
65	86
66	83
67	70
68	89
69	70
70	79
71	102
72	79