A237253 - cp's OEIS frontend

A237253 Number of ordered ways to write n = k + m with k > 0 and m > 0 such that phi(k) - 1, phi(k) + 1 and prime(prime(prime(m))) - 2 are all prime, where phi(.) is Euler's totient function.

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

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

cp's OEIS Frontend

A237253 Number of ordered ways to write n = k + m with k > 0 and m > 0 such that phi(k) - 1, phi(k) + 1 and prime(prime(prime(m))) - 2 are 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	1
7	0
8	2
9	1
10	2
11	2
12	1
13	2
14	1
15	2
16	1
17	1
18	1
19	2
20	2
21	3
22	4
23	2
24	2
25	1
26	2
27	3
28	3
29	3
30	2
31	4
32	5
33	4
34	3
35	4
36	3
37	5
38	4
39	4
40	6
41	6
42	7
43	5
44	5
45	6
46	3
47	4
48	3
49	6
50	5
51	6
52	5
53	3
54	6
55	5
56	6
57	3
58	3
59	5
60	3
61	5
62	4
63	3
64	4
65	3
66	6
67	4
68	3
69	1
70	1
71	4
72	3
73	4
74	4
75	4
76	5
77	6
78	7
79	3
80	3

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

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