A233544 - cp's OEIS frontend

A233544 Number of ways to write n = k^2 + m with k > 0 and m >= k^2 such that sigma(k^2) + phi(m) is prime, where sigma(k^2) is the sum of all (positive) divisors of k^2, and phi(.) is Euler's totient function (A000010).

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

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

cp's OEIS Frontend

A233544 Number of ways to write n = k^2 + m with k > 0 and m >= k^2 such that sigma(k^2) + phi(m) is prime, where sigma(k^2) is the sum of all (positive) divisors of k^2, and phi(.) is Euler's totient function (A000010).

Table of values

List of values

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

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

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