A110173 - cp's OEIS frontend

A110173 Least k such that phi(n) = phi(k) + phi(n-k) for 0 or 0 if there is no such k, where phi is Euler's totient function.

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

[0, 0, 1, 2, 0, 0, 0, 4, 4, 4, 0, 6, 0, 4, 5, 8, 0, 6, 0, 6, 5, 6, 0, 6, 6, 4, 11, 6, 0, 0, 0, 16, 6, 8, 10, 12, 0, 4, 13, 12, 0, 12, 0, 6, 7, 8, 0, 12, 0, 10, 16, 6, 0, 6, 26, 12, 19, 26, 0, 30, 0, 4, 12, 32, 24, 24, 0, 6, 23, 28, 0, 18, 0, 10, 12, 8, 24, 12, 0, 24, 0, 8, 0, 24, 8, 4, 6, 12, 0, 30]

cp's OEIS Frontend

A110173 Least k such that phi(n) = phi(k) + phi(n-k) for 0 or 0 if there is no such k, where phi is Euler's totient function.

Table of values

List of values

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

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

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