A104280 - cp's OEIS frontend

A104280 Numbers n such that 2n+1 is not prime and 2n-1 is prime.

n	a(n)
1	4
2	7
3	10
4	12
5	16
6	19
7	22
8	24
9	27
10	31
11	34
12	37
13	40
14	42
15	45
16	49
17	52
18	55
19	57
20	64
21	66
22	70
23	76
24	79
25	82
26	84
27	87
28	91
29	97
30	100
31	106
32	112
33	115
34	117
35	121
36	126
37	129
38	132
39	136
40	139
41	142
42	147
43	154
44	157
45	159
46	166
47	169
48	175
49	177
50	180
51	184
52	187
53	190
54	192
55	195
56	199
57	201
58	205
59	211
60	217

[4, 7, 10, 12, 16, 19, 22, 24, 27, 31, 34, 37, 40, 42, 45, 49, 52, 55, 57, 64, 66, 70, 76, 79, 82, 84, 87, 91, 97, 100, 106, 112, 115, 117, 121, 126, 129, 132, 136, 139, 142, 147, 154, 157, 159, 166, 169, 175, 177, 180, 184, 187, 190, 192, 195, 199, 201, 205, 211, 217]

cp's OEIS Frontend

A104280 Numbers n such that 2n+1 is not prime and 2n-1 is prime.

Table of values

List of values

n	a(n)
1	4
2	7
3	10
4	12
5	16
6	19
7	22
8	24
9	27
10	31
11	34
12	37
13	40
14	42
15	45
16	49
17	52
18	55
19	57
20	64
21	66
22	70
23	76
24	79
25	82
26	84
27	87
28	91
29	97
30	100
31	106
32	112
33	115
34	117
35	121
36	126
37	129
38	132
39	136
40	139
41	142
42	147
43	154
44	157
45	159
46	166
47	169
48	175
49	177
50	180
51	184
52	187
53	190
54	192
55	195
56	199
57	201
58	205
59	211
60	217

n	a(n)
1	4
2	7
3	10
4	12
5	16
6	19
7	22
8	24
9	27
10	31
11	34
12	37
13	40
14	42
15	45
16	49
17	52
18	55
19	57
20	64
21	66
22	70
23	76
24	79
25	82
26	84
27	87
28	91
29	97
30	100
31	106
32	112
33	115
34	117
35	121
36	126
37	129
38	132
39	136
40	139
41	142
42	147
43	154
44	157
45	159
46	166
47	169
48	175
49	177
50	180
51	184
52	187
53	190
54	192
55	195
56	199
57	201
58	205
59	211
60	217

n	a(n)
1	4
2	7
3	10
4	12
5	16
6	19
7	22
8	24
9	27
10	31
11	34
12	37
13	40
14	42
15	45
16	49
17	52
18	55
19	57
20	64
21	66
22	70
23	76
24	79
25	82
26	84
27	87
28	91
29	97
30	100
31	106
32	112
33	115
34	117
35	121
36	126
37	129
38	132
39	136
40	139
41	142
42	147
43	154
44	157
45	159
46	166
47	169
48	175
49	177
50	180
51	184
52	187
53	190
54	192
55	195
56	199
57	201
58	205
59	211
60	217