A131883 - cp's OEIS frontend

A131883 a(n) = the minimum value from among (phi(n+1),phi(n+2),phi(n+3),...,phi(2n)), where phi(m) (A000010) is the number of positive integers which are coprime to m and are <= m.

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

[1, 2, 2, 2, 2, 4, 4, 4, 4, 4, 4, 6, 6, 6, 6, 6, 6, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 20, 20, 20, 20, 20, 20, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24]

cp's OEIS Frontend

A131883 a(n) = the minimum value from among (phi(n+1),phi(n+2),phi(n+3),...,phi(2n)), where phi(m) (A000010) is the number of positive integers which are coprime to m and are <= m.

Table of values

List of values

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

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

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