A237595 - cp's OEIS frontend

A237595 a(n) = |{1 <= k <= n: n + pi(k^2) is prime}|, where pi(.) is given by A000720.

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

[0, 1, 3, 0, 3, 1, 3, 3, 3, 1, 5, 2, 6, 3, 4, 2, 6, 3, 7, 3, 2, 6, 8, 1, 10, 3, 5, 8, 9, 2, 9, 6, 3, 5, 14, 5, 11, 6, 9, 3, 13, 8, 11, 8, 8, 6, 8, 8, 11, 9, 6, 12, 15, 10, 11, 5, 11, 12, 13, 9, 12, 9, 5, 17, 15, 9, 18, 13, 11, 12]

cp's OEIS Frontend

A237595 a(n) = |{1 <= k <= n: n + pi(k^2) is prime}|, where pi(.) is given by A000720.

Table of values

List of values

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

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

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