A234344 - cp's OEIS frontend

A234344 a(n) = |{0 < k < n: 2^{phi(k)/2} + 3^{phi(n-k)/2} is prime}|, where phi(.) is Euler's totient function.

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

[0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 6, 8, 7, 9, 12, 12, 10, 10, 10, 10, 16, 7, 11, 9, 6, 14, 11, 17, 12, 15, 15, 17, 16, 15, 19, 18, 12, 13, 9, 20, 11, 8, 17, 19, 19, 12, 17, 14, 16, 9, 21, 16, 13, 12, 16, 19, 17, 11, 21, 15, 16, 15, 17, 19, 16, 23, 11, 20, 15]

cp's OEIS Frontend

A234344 a(n) = |{0 < k < n: 2^{phi(k)/2} + 3^{phi(n-k)/2} 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	0
5	0
6	1
7	2
8	3
9	4
10	5
11	6
12	7
13	8
14	6
15	8
16	7
17	9
18	12
19	12
20	10
21	10
22	10
23	10
24	16
25	7
26	11
27	9
28	6
29	14
30	11
31	17
32	12
33	15
34	15
35	17
36	16
37	15
38	19
39	18
40	12
41	13
42	9
43	20
44	11
45	8
46	17
47	19
48	19
49	12
50	17
51	14
52	16
53	9
54	21
55	16
56	13
57	12
58	16
59	19
60	17
61	11
62	21
63	15
64	16
65	15
66	17
67	19
68	16
69	23
70	11
71	20
72	15

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

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