A238597 - cp's OEIS frontend

A238597 Number of primes p < 2n with 2pi(p) + 1 and p*(2n-1) - 2 both prime, where pi(.) is given by A000720.

n	a(n)
1	0
2	1
3	2
4	1
5	1
6	2
7	2
8	4
9	1
10	1
11	5
12	3
13	1
14	3
15	1
16	2
17	4
18	3
19	3
20	2
21	2
22	3
23	4
24	3
25	1
26	5
27	3
28	1
29	3
30	2
31	4
32	5
33	2
34	2
35	2
36	3
37	3
38	6
39	3
40	3
41	4
42	2
43	4
44	5
45	3
46	4
47	5
48	3
49	2
50	6
51	2
52	3
53	8
54	1
55	1
56	5
57	5
58	3
59	5
60	4
61	4
62	6
63	2
64	3
65	3
66	4
67	3
68	7
69	3
70	1
71	7
72	4
73	4
74	5
75	4
76	3
77	8
78	4
79	1
80	7

[0, 1, 2, 1, 1, 2, 2, 4, 1, 1, 5, 3, 1, 3, 1, 2, 4, 3, 3, 2, 2, 3, 4, 3, 1, 5, 3, 1, 3, 2, 4, 5, 2, 2, 2, 3, 3, 6, 3, 3, 4, 2, 4, 5, 3, 4, 5, 3, 2, 6, 2, 3, 8, 1, 1, 5, 5, 3, 5, 4, 4, 6, 2, 3, 3, 4, 3, 7, 3, 1, 7, 4, 4, 5, 4, 3, 8, 4, 1, 7]

cp's OEIS Frontend

A238597 Number of primes p < 2n with 2pi(p) + 1 and p*(2n-1) - 2 both prime, where pi(.) is given by A000720.

Table of values

List of values

n	a(n)
1	0
2	1
3	2
4	1
5	1
6	2
7	2
8	4
9	1
10	1
11	5
12	3
13	1
14	3
15	1
16	2
17	4
18	3
19	3
20	2
21	2
22	3
23	4
24	3
25	1
26	5
27	3
28	1
29	3
30	2
31	4
32	5
33	2
34	2
35	2
36	3
37	3
38	6
39	3
40	3
41	4
42	2
43	4
44	5
45	3
46	4
47	5
48	3
49	2
50	6
51	2
52	3
53	8
54	1
55	1
56	5
57	5
58	3
59	5
60	4
61	4
62	6
63	2
64	3
65	3
66	4
67	3
68	7
69	3
70	1
71	7
72	4
73	4
74	5
75	4
76	3
77	8
78	4
79	1
80	7

n	a(n)
1	0
2	1
3	2
4	1
5	1
6	2
7	2
8	4
9	1
10	1
11	5
12	3
13	1
14	3
15	1
16	2
17	4
18	3
19	3
20	2
21	2
22	3
23	4
24	3
25	1
26	5
27	3
28	1
29	3
30	2
31	4
32	5
33	2
34	2
35	2
36	3
37	3
38	6
39	3
40	3
41	4
42	2
43	4
44	5
45	3
46	4
47	5
48	3
49	2
50	6
51	2
52	3
53	8
54	1
55	1
56	5
57	5
58	3
59	5
60	4
61	4
62	6
63	2
64	3
65	3
66	4
67	3
68	7
69	3
70	1
71	7
72	4
73	4
74	5
75	4
76	3
77	8
78	4
79	1
80	7

cp's OEIS Frontend

A238597 Number of primes p < 2*n with 2*pi(p) + 1 and p*(2n-1) - 2 both prime, where pi(.) is given by A000720.

Table of values

List of values

A238597 Number of primes p < 2n with 2pi(p) + 1 and p*(2n-1) - 2 both prime, where pi(.) is given by A000720.

n	a(n)
1	0
2	1
3	2
4	1
5	1
6	2
7	2
8	4
9	1
10	1
11	5
12	3
13	1
14	3
15	1
16	2
17	4
18	3
19	3
20	2
21	2
22	3
23	4
24	3
25	1
26	5
27	3
28	1
29	3
30	2
31	4
32	5
33	2
34	2
35	2
36	3
37	3
38	6
39	3
40	3
41	4
42	2
43	4
44	5
45	3
46	4
47	5
48	3
49	2
50	6
51	2
52	3
53	8
54	1
55	1
56	5
57	5
58	3
59	5
60	4
61	4
62	6
63	2
64	3
65	3
66	4
67	3
68	7
69	3
70	1
71	7
72	4
73	4
74	5
75	4
76	3
77	8
78	4
79	1
80	7