A216504 - cp's OEIS frontend

A216504 Number of values of k for which n can be written in the form a^2 + k*b^2, a >= 0, b >= 0, k > 0. a(n) = 0 if there are infinitely many such k.

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

[0, 2, 2, 0, 3, 3, 3, 5, 0, 4, 4, 5, 6, 4, 4, 0, 7, 6, 6, 7, 6, 6, 5, 8, 0, 6, 7, 8, 9, 6, 7, 10, 8, 8, 6, 0, 11, 7, 7, 11, 12, 7, 9, 11, 11, 8, 7, 11, 0, 9, 8, 13, 12, 10, 8, 12, 12, 10, 9, 11, 15, 8, 11, 0, 12, 9, 11, 15, 12, 10, 9, 17, 18, 10, 11, 16, 12, 9, 12, 15, 0, 12, 10, 14, 14, 11, 10, 17, 18, 13, 11, 15, 15, 12, 10, 17, 21, 12, 14, 0]

cp's OEIS Frontend

A216504 Number of values of k for which n can be written in the form a^2 + k*b^2, a >= 0, b >= 0, k > 0. a(n) = 0 if there are infinitely many such k.

Table of values

List of values

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

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

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