A299143 - cp's OEIS frontend

A299143 a(n) is the least k > n such that gcd(k,n) > 1 and gcd(k+1,n+1) > 1.

n	a(n)
2	8
3	9
4	14
5	15
6	20
7	21
8	14
9	15
10	32
11	33
12	38
13	39
14	20
15	21
16	50
17	51
18	56
19	57
20	26
21	27
22	68
23	69
24	34
25	35
26	32
27	33
28	86
29	87
30	92
31	93
32	38
33	39
34	44
35	45
36	110
37	111
38	44
39	45
40	122
41	123
42	128
43	129
44	50
45	51
46	140
47	141
48	62
49	63
50	56
51	57
52	158
53	159
54	64
55	65
56	62
57	63
58	176
59	177
60	182
61	183
62	68
63	69

[8, 9, 14, 15, 20, 21, 14, 15, 32, 33, 38, 39, 20, 21, 50, 51, 56, 57, 26, 27, 68, 69, 34, 35, 32, 33, 86, 87, 92, 93, 38, 39, 44, 45, 110, 111, 44, 45, 122, 123, 128, 129, 50, 51, 140, 141, 62, 63, 56, 57, 158, 159, 64, 65, 62, 63, 176, 177, 182, 183, 68, 69]

cp's OEIS Frontend

A299143 a(n) is the least k > n such that gcd(k,n) > 1 and gcd(k+1,n+1) > 1.

Table of values

List of values

n	a(n)
2	8
3	9
4	14
5	15
6	20
7	21
8	14
9	15
10	32
11	33
12	38
13	39
14	20
15	21
16	50
17	51
18	56
19	57
20	26
21	27
22	68
23	69
24	34
25	35
26	32
27	33
28	86
29	87
30	92
31	93
32	38
33	39
34	44
35	45
36	110
37	111
38	44
39	45
40	122
41	123
42	128
43	129
44	50
45	51
46	140
47	141
48	62
49	63
50	56
51	57
52	158
53	159
54	64
55	65
56	62
57	63
58	176
59	177
60	182
61	183
62	68
63	69

n	a(n)
2	8
3	9
4	14
5	15
6	20
7	21
8	14
9	15
10	32
11	33
12	38
13	39
14	20
15	21
16	50
17	51
18	56
19	57
20	26
21	27
22	68
23	69
24	34
25	35
26	32
27	33
28	86
29	87
30	92
31	93
32	38
33	39
34	44
35	45
36	110
37	111
38	44
39	45
40	122
41	123
42	128
43	129
44	50
45	51
46	140
47	141
48	62
49	63
50	56
51	57
52	158
53	159
54	64
55	65
56	62
57	63
58	176
59	177
60	182
61	183
62	68
63	69

n	a(n)
2	8
3	9
4	14
5	15
6	20
7	21
8	14
9	15
10	32
11	33
12	38
13	39
14	20
15	21
16	50
17	51
18	56
19	57
20	26
21	27
22	68
23	69
24	34
25	35
26	32
27	33
28	86
29	87
30	92
31	93
32	38
33	39
34	44
35	45
36	110
37	111
38	44
39	45
40	122
41	123
42	128
43	129
44	50
45	51
46	140
47	141
48	62
49	63
50	56
51	57
52	158
53	159
54	64
55	65
56	62
57	63
58	176
59	177
60	182
61	183
62	68
63	69