A233654 - cp's OEIS frontend

A233654 |{prime p < n: n - p = sigma(k) for some k > 0}|, where sigma(k) is the sum of all (positive) divisors of k.

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

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

cp's OEIS Frontend

A233654 |{prime p < n: n - p = sigma(k) for some k > 0}|, where sigma(k) is the sum of all (positive) divisors of k.

Table of values

List of values

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

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

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