A237578 - cp's OEIS frontend

A237578 a(n) = |{0 < k < n: pi(k*n) is prime}|, where pi(.) is given by A000720.

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

[0, 0, 2, 2, 1, 3, 2, 1, 2, 2, 4, 4, 1, 4, 2, 5, 5, 6, 2, 5, 4, 6, 3, 7, 3, 3, 7, 5, 5, 5, 10, 9, 3, 7, 6, 5, 12, 3, 3, 9, 10, 11, 12, 7, 3, 5, 11, 9, 7, 10, 12, 9, 10, 8, 12, 11, 10, 17, 15, 13, 14, 18, 4, 17, 10, 9, 15, 11, 14, 11, 23, 11, 9, 13, 12, 12, 12, 11, 14, 16]

cp's OEIS Frontend

A237578 a(n) = |{0 < k < n: pi(k*n) is prime}|, where pi(.) is given by A000720.

Table of values

List of values

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

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

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