A232442 - cp's OEIS frontend

A232442 a(n) = |{0 < k < n: mprime(m) - 1 and mprime(m) + 1 are both prime with m = sigma(k) + phi(n-k)}|, where sigma(k) is the sum of all positive divisors of k and phi(.) is Euler's totient function.

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

[0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 2, 1, 1, 0, 0, 1, 1, 6, 1, 2, 2, 0, 0, 1, 2, 3, 0, 1, 2, 0, 1, 2, 4, 1, 1, 0, 1, 2, 2, 2, 4, 0, 0, 1, 2, 0, 3, 3, 3, 2, 0, 1, 1, 2, 1, 2, 0, 1, 1, 14, 3, 2, 2, 2, 2, 3, 4, 5, 3, 2, 3, 1, 3, 3, 4, 6, 3, 0, 5, 3, 1, 0, 5, 2, 0, 3, 6, 1]

cp's OEIS Frontend

A232442 a(n) = |{0 < k < n: mprime(m) - 1 and mprime(m) + 1 are both prime with m = sigma(k) + phi(n-k)}|, where sigma(k) is the sum of all positive divisors of k and phi(.) is Euler's totient function.

Table of values

List of values

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

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

cp's OEIS Frontend

A232442 a(n) = |{0 < k < n: m*prime(m) - 1 and m*prime(m) + 1 are both prime with m = sigma(k) + phi(n-k)}|, where sigma(k) is the sum of all positive divisors of k and phi(.) is Euler's totient function.

Table of values

List of values

A232442 a(n) = |{0 < k < n: mprime(m) - 1 and mprime(m) + 1 are both prime with m = sigma(k) + phi(n-k)}|, where sigma(k) is the sum of all positive divisors of k and phi(.) is Euler's totient function.

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