A237168 - cp's OEIS frontend

A237168 Number of ways to write 2n - 1 = 2p + q with p, q, phi(p+1) - 1 and phi(p+1) + 1 all prime, where phi(.) is Euler's totient function.

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

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

cp's OEIS Frontend

A237168 Number of ways to write 2n - 1 = 2p + q with p, q, phi(p+1) - 1 and phi(p+1) + 1 all 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	0
7	0
8	0
9	1
10	1
11	1
12	0
13	2
14	2
15	2
16	2
17	3
18	1
19	3
20	3
21	2
22	2
23	4
24	1
25	1
26	3
27	2
28	2
29	3
30	1
31	1
32	3
33	2
34	2
35	2
36	1
37	2
38	3
39	2
40	2
41	4
42	1
43	4
44	5
45	2
46	1
47	6
48	3
49	3
50	2
51	3
52	2
53	5
54	1
55	2
56	5
57	3
58	3
59	4
60	3
61	2
62	6
63	4
64	4
65	5
66	2
67	3
68	7
69	2
70	2

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

cp's OEIS Frontend

A237168 Number of ways to write 2*n - 1 = 2*p + q with p, q, phi(p+1) - 1 and phi(p+1) + 1 all prime, where phi(.) is Euler's totient function.

Table of values

List of values

A237168 Number of ways to write 2n - 1 = 2p + q with p, q, phi(p+1) - 1 and phi(p+1) + 1 all prime, where phi(.) is Euler's totient function.

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