A002246 - cp's OEIS frontend

A002246 a(1) = 3; for n > 1, a(n) = 4*phi(n); given a rational number r = p/q, where q>0, (p,q)=1, define its height to be max{|p|,q}; then a(n) = number of rational numbers of height n.

n	a(n)
1	3
2	4
3	8
4	8
5	16
6	8
7	24
8	16
9	24
10	16
11	40
12	16
13	48
14	24
15	32
16	32
17	64
18	24
19	72
20	32
21	48
22	40
23	88
24	32
25	80
26	48
27	72
28	48
29	112
30	32
31	120
32	64
33	80
34	64
35	96
36	48
37	144
38	72
39	96
40	64
41	160
42	48
43	168
44	80
45	96
46	88
47	184
48	64
49	168
50	80
51	128
52	96
53	208
54	72
55	160
56	96
57	144
58	112
59	232
60	64
61	240
62	120
63	144
64	128
65	192
66	80
67	264

[3, 4, 8, 8, 16, 8, 24, 16, 24, 16, 40, 16, 48, 24, 32, 32, 64, 24, 72, 32, 48, 40, 88, 32, 80, 48, 72, 48, 112, 32, 120, 64, 80, 64, 96, 48, 144, 72, 96, 64, 160, 48, 168, 80, 96, 88, 184, 64, 168, 80, 128, 96, 208, 72, 160, 96, 144, 112, 232, 64, 240, 120, 144, 128, 192, 80, 264]

cp's OEIS Frontend

A002246 a(1) = 3; for n > 1, a(n) = 4*phi(n); given a rational number r = p/q, where q>0, (p,q)=1, define its height to be max{|p|,q}; then a(n) = number of rational numbers of height n.

Table of values

List of values

n	a(n)
1	3
2	4
3	8
4	8
5	16
6	8
7	24
8	16
9	24
10	16
11	40
12	16
13	48
14	24
15	32
16	32
17	64
18	24
19	72
20	32
21	48
22	40
23	88
24	32
25	80
26	48
27	72
28	48
29	112
30	32
31	120
32	64
33	80
34	64
35	96
36	48
37	144
38	72
39	96
40	64
41	160
42	48
43	168
44	80
45	96
46	88
47	184
48	64
49	168
50	80
51	128
52	96
53	208
54	72
55	160
56	96
57	144
58	112
59	232
60	64
61	240
62	120
63	144
64	128
65	192
66	80
67	264

n	a(n)
1	3
2	4
3	8
4	8
5	16
6	8
7	24
8	16
9	24
10	16
11	40
12	16
13	48
14	24
15	32
16	32
17	64
18	24
19	72
20	32
21	48
22	40
23	88
24	32
25	80
26	48
27	72
28	48
29	112
30	32
31	120
32	64
33	80
34	64
35	96
36	48
37	144
38	72
39	96
40	64
41	160
42	48
43	168
44	80
45	96
46	88
47	184
48	64
49	168
50	80
51	128
52	96
53	208
54	72
55	160
56	96
57	144
58	112
59	232
60	64
61	240
62	120
63	144
64	128
65	192
66	80
67	264

n	a(n)
1	3
2	4
3	8
4	8
5	16
6	8
7	24
8	16
9	24
10	16
11	40
12	16
13	48
14	24
15	32
16	32
17	64
18	24
19	72
20	32
21	48
22	40
23	88
24	32
25	80
26	48
27	72
28	48
29	112
30	32
31	120
32	64
33	80
34	64
35	96
36	48
37	144
38	72
39	96
40	64
41	160
42	48
43	168
44	80
45	96
46	88
47	184
48	64
49	168
50	80
51	128
52	96
53	208
54	72
55	160
56	96
57	144
58	112
59	232
60	64
61	240
62	120
63	144
64	128
65	192
66	80
67	264