A236470 - cp's OEIS frontend

A236470 a(n) = |{0 < k < n: p = prime(k) + phi(n-k), p + 2 and prime(p) + 2 are all prime}|, where phi(.) is Euler's totient function.

n	a(n)
1	0
2	1
3	1
4	0
5	1
6	1
7	0
8	1
9	0
10	0
11	1
12	1
13	0
14	2
15	1
16	2
17	1
18	1
19	1
20	1
21	0
22	2
23	2
24	2
25	0
26	1
27	0
28	1
29	1
30	0
31	3
32	0
33	1
34	0
35	1
36	3
37	0
38	1
39	1
40	1
41	0
42	1
43	0
44	0
45	1
46	2
47	1
48	0
49	0
50	0
51	0
52	2
53	0
54	1
55	0
56	0
57	0
58	0
59	1
60	1
61	0
62	0
63	2
64	1
65	0
66	1
67	1
68	0
69	0
70	0
71	0
72	0
73	0
74	0
75	0
76	0
77	2
78	0
79	2
80	0
81	0
82	0
83	0
84	0
85	1
86	0
87	0
88	0
89	0
90	0
91	1
92	0
93	0
94	0
95	0
96	0
97	1
98	0
99	0
100	0

[0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 2, 1, 2, 1, 1, 1, 1, 0, 2, 2, 2, 0, 1, 0, 1, 1, 0, 3, 0, 1, 0, 1, 3, 0, 1, 1, 1, 0, 1, 0, 0, 1, 2, 1, 0, 0, 0, 0, 2, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 2, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0]

cp's OEIS Frontend

A236470 a(n) = |{0 < k < n: p = prime(k) + phi(n-k), p + 2 and prime(p) + 2 are all prime}|, where phi(.) is Euler's totient function.

Table of values

List of values

n	a(n)
1	0
2	1
3	1
4	0
5	1
6	1
7	0
8	1
9	0
10	0
11	1
12	1
13	0
14	2
15	1
16	2
17	1
18	1
19	1
20	1
21	0
22	2
23	2
24	2
25	0
26	1
27	0
28	1
29	1
30	0
31	3
32	0
33	1
34	0
35	1
36	3
37	0
38	1
39	1
40	1
41	0
42	1
43	0
44	0
45	1
46	2
47	1
48	0
49	0
50	0
51	0
52	2
53	0
54	1
55	0
56	0
57	0
58	0
59	1
60	1
61	0
62	0
63	2
64	1
65	0
66	1
67	1
68	0
69	0
70	0
71	0
72	0
73	0
74	0
75	0
76	0
77	2
78	0
79	2
80	0
81	0
82	0
83	0
84	0
85	1
86	0
87	0
88	0
89	0
90	0
91	1
92	0
93	0
94	0
95	0
96	0
97	1
98	0
99	0
100	0

n	a(n)
1	0
2	1
3	1
4	0
5	1
6	1
7	0
8	1
9	0
10	0
11	1
12	1
13	0
14	2
15	1
16	2
17	1
18	1
19	1
20	1
21	0
22	2
23	2
24	2
25	0
26	1
27	0
28	1
29	1
30	0
31	3
32	0
33	1
34	0
35	1
36	3
37	0
38	1
39	1
40	1
41	0
42	1
43	0
44	0
45	1
46	2
47	1
48	0
49	0
50	0
51	0
52	2
53	0
54	1
55	0
56	0
57	0
58	0
59	1
60	1
61	0
62	0
63	2
64	1
65	0
66	1
67	1
68	0
69	0
70	0
71	0
72	0
73	0
74	0
75	0
76	0
77	2
78	0
79	2
80	0
81	0
82	0
83	0
84	0
85	1
86	0
87	0
88	0
89	0
90	0
91	1
92	0
93	0
94	0
95	0
96	0
97	1
98	0
99	0
100	0

n	a(n)
1	0
2	1
3	1
4	0
5	1
6	1
7	0
8	1
9	0
10	0
11	1
12	1
13	0
14	2
15	1
16	2
17	1
18	1
19	1
20	1
21	0
22	2
23	2
24	2
25	0
26	1
27	0
28	1
29	1
30	0
31	3
32	0
33	1
34	0
35	1
36	3
37	0
38	1
39	1
40	1
41	0
42	1
43	0
44	0
45	1
46	2
47	1
48	0
49	0
50	0
51	0
52	2
53	0
54	1
55	0
56	0
57	0
58	0
59	1
60	1
61	0
62	0
63	2
64	1
65	0
66	1
67	1
68	0
69	0
70	0
71	0
72	0
73	0
74	0
75	0
76	0
77	2
78	0
79	2
80	0
81	0
82	0
83	0
84	0
85	1
86	0
87	0
88	0
89	0
90	0
91	1
92	0
93	0
94	0
95	0
96	0
97	1
98	0
99	0
100	0