A236567 - cp's OEIS frontend

A236567 a(n) = |{0 < k < n - 2: k + phi(n-k)/2 is a square}|, where phi(.) is Euler's totient function.

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

[0, 0, 0, 0, 0, 1, 2, 1, 1, 2, 1, 3, 1, 2, 4, 1, 1, 2, 4, 3, 2, 3, 1, 3, 2, 3, 3, 4, 3, 1, 8, 3, 3, 2, 4, 4, 2, 2, 5, 6, 4, 6, 3, 2, 5, 4, 4, 5, 4, 1, 8, 6, 3, 3, 5, 6, 3, 4, 5, 9, 5, 2, 3, 6, 6, 5, 4, 4, 6, 8, 6, 8, 4, 3, 5, 8, 4, 1, 6, 6, 6, 3, 9, 8, 5, 4, 6, 7, 7, 6, 7, 5, 6, 8, 3, 10, 5, 5, 5, 4]

cp's OEIS Frontend

A236567 a(n) = |{0 < k < n - 2: k + phi(n-k)/2 is a square}|, where phi(.) is Euler's totient function.

Table of values

List of values

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

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

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