A234347 - cp's OEIS frontend

A234347 a(n) = |{0 < k < n: 3^k + 3^{phi(n-k)/2} - 1 is prime}|, where phi(.) is Euler's totient function.

n	a(n)
1	0
2	0
3	0
4	1
5	2
6	3
7	4
8	3
9	3
10	5
11	3
12	5
13	6
14	7
15	2
16	6
17	7
18	11
19	7
20	3
21	6
22	8
23	7
24	4
25	11
26	8
27	8
28	6
29	6
30	10
31	7
32	6
33	8
34	5
35	6
36	4
37	8
38	4
39	6
40	6
41	6
42	11
43	10
44	3
45	9
46	6
47	6
48	4
49	10
50	6
51	7
52	3
53	4
54	9
55	8
56	9
57	7
58	9
59	5
60	9
61	7
62	9
63	8
64	4
65	6
66	9
67	10
68	7
69	8
70	9
71	10
72	5
73	6
74	12
75	5
76	6
77	9
78	10
79	8
80	9
81	7
82	8
83	8
84	10

[0, 0, 0, 1, 2, 3, 4, 3, 3, 5, 3, 5, 6, 7, 2, 6, 7, 11, 7, 3, 6, 8, 7, 4, 11, 8, 8, 6, 6, 10, 7, 6, 8, 5, 6, 4, 8, 4, 6, 6, 6, 11, 10, 3, 9, 6, 6, 4, 10, 6, 7, 3, 4, 9, 8, 9, 7, 9, 5, 9, 7, 9, 8, 4, 6, 9, 10, 7, 8, 9, 10, 5, 6, 12, 5, 6, 9, 10, 8, 9, 7, 8, 8, 10]

cp's OEIS Frontend

A234347 a(n) = |{0 < k < n: 3^k + 3^{phi(n-k)/2} - 1 is prime}|, where phi(.) is Euler's totient function.

Table of values

List of values

n	a(n)
1	0
2	0
3	0
4	1
5	2
6	3
7	4
8	3
9	3
10	5
11	3
12	5
13	6
14	7
15	2
16	6
17	7
18	11
19	7
20	3
21	6
22	8
23	7
24	4
25	11
26	8
27	8
28	6
29	6
30	10
31	7
32	6
33	8
34	5
35	6
36	4
37	8
38	4
39	6
40	6
41	6
42	11
43	10
44	3
45	9
46	6
47	6
48	4
49	10
50	6
51	7
52	3
53	4
54	9
55	8
56	9
57	7
58	9
59	5
60	9
61	7
62	9
63	8
64	4
65	6
66	9
67	10
68	7
69	8
70	9
71	10
72	5
73	6
74	12
75	5
76	6
77	9
78	10
79	8
80	9
81	7
82	8
83	8
84	10

n	a(n)
1	0
2	0
3	0
4	1
5	2
6	3
7	4
8	3
9	3
10	5
11	3
12	5
13	6
14	7
15	2
16	6
17	7
18	11
19	7
20	3
21	6
22	8
23	7
24	4
25	11
26	8
27	8
28	6
29	6
30	10
31	7
32	6
33	8
34	5
35	6
36	4
37	8
38	4
39	6
40	6
41	6
42	11
43	10
44	3
45	9
46	6
47	6
48	4
49	10
50	6
51	7
52	3
53	4
54	9
55	8
56	9
57	7
58	9
59	5
60	9
61	7
62	9
63	8
64	4
65	6
66	9
67	10
68	7
69	8
70	9
71	10
72	5
73	6
74	12
75	5
76	6
77	9
78	10
79	8
80	9
81	7
82	8
83	8
84	10

n	a(n)
1	0
2	0
3	0
4	1
5	2
6	3
7	4
8	3
9	3
10	5
11	3
12	5
13	6
14	7
15	2
16	6
17	7
18	11
19	7
20	3
21	6
22	8
23	7
24	4
25	11
26	8
27	8
28	6
29	6
30	10
31	7
32	6
33	8
34	5
35	6
36	4
37	8
38	4
39	6
40	6
41	6
42	11
43	10
44	3
45	9
46	6
47	6
48	4
49	10
50	6
51	7
52	3
53	4
54	9
55	8
56	9
57	7
58	9
59	5
60	9
61	7
62	9
63	8
64	4
65	6
66	9
67	10
68	7
69	8
70	9
71	10
72	5
73	6
74	12
75	5
76	6
77	9
78	10
79	8
80	9
81	7
82	8
83	8
84	10