A237203 - cp's OEIS frontend

A237203 Least positive integer k < n/2 with phi(k)*phi(n-k) a square, or 0 if such a number k does not exist.

n	a(n)
1	0
2	0
3	1
4	0
5	0
6	1
7	2
8	0
9	1
10	2
11	1
12	2
13	1
14	2
15	5
16	7
17	5
18	1
19	2
20	4
21	6
22	3
23	3
24	4
25	6
26	6
27	3
28	4
29	12
30	3
31	4
32	14
33	1
34	2
35	1
36	2
37	5
38	1
39	2
40	8
41	1
42	2
43	16
44	6
45	5
46	7
47	10
48	8
49	1
50	2
51	17
52	7
53	5
54	3
55	4
56	8
57	3
58	1
59	2
60	6
61	1
62	2
63	7
64	1
65	2
66	11
67	3
68	4
69	12
70	6

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

cp's OEIS Frontend

A237203 Least positive integer k < n/2 with phi(k)*phi(n-k) a square, or 0 if such a number k does not exist.

Table of values

List of values

n	a(n)
1	0
2	0
3	1
4	0
5	0
6	1
7	2
8	0
9	1
10	2
11	1
12	2
13	1
14	2
15	5
16	7
17	5
18	1
19	2
20	4
21	6
22	3
23	3
24	4
25	6
26	6
27	3
28	4
29	12
30	3
31	4
32	14
33	1
34	2
35	1
36	2
37	5
38	1
39	2
40	8
41	1
42	2
43	16
44	6
45	5
46	7
47	10
48	8
49	1
50	2
51	17
52	7
53	5
54	3
55	4
56	8
57	3
58	1
59	2
60	6
61	1
62	2
63	7
64	1
65	2
66	11
67	3
68	4
69	12
70	6

n	a(n)
1	0
2	0
3	1
4	0
5	0
6	1
7	2
8	0
9	1
10	2
11	1
12	2
13	1
14	2
15	5
16	7
17	5
18	1
19	2
20	4
21	6
22	3
23	3
24	4
25	6
26	6
27	3
28	4
29	12
30	3
31	4
32	14
33	1
34	2
35	1
36	2
37	5
38	1
39	2
40	8
41	1
42	2
43	16
44	6
45	5
46	7
47	10
48	8
49	1
50	2
51	17
52	7
53	5
54	3
55	4
56	8
57	3
58	1
59	2
60	6
61	1
62	2
63	7
64	1
65	2
66	11
67	3
68	4
69	12
70	6

n	a(n)
1	0
2	0
3	1
4	0
5	0
6	1
7	2
8	0
9	1
10	2
11	1
12	2
13	1
14	2
15	5
16	7
17	5
18	1
19	2
20	4
21	6
22	3
23	3
24	4
25	6
26	6
27	3
28	4
29	12
30	3
31	4
32	14
33	1
34	2
35	1
36	2
37	5
38	1
39	2
40	8
41	1
42	2
43	16
44	6
45	5
46	7
47	10
48	8
49	1
50	2
51	17
52	7
53	5
54	3
55	4
56	8
57	3
58	1
59	2
60	6
61	1
62	2
63	7
64	1
65	2
66	11
67	3
68	4
69	12
70	6