A236765 - cp's OEIS frontend

A236765 Number of ways to write n = k^2 + m with k > 1 and m > 1 such that sigma(k^2) + prime(m) - 1 is prime, where sigma(j) denotes the sum of all positive divisors of j.

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

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

cp's OEIS Frontend

A236765 Number of ways to write n = k^2 + m with k > 1 and m > 1 such that sigma(k^2) + prime(m) - 1 is prime, where sigma(j) denotes the sum of all positive divisors of j.

Table of values

List of values

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

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

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