A273724 - cp's OEIS frontend

A273724 Place n equally-spaced points around a circle, labeled 0,1,2,...,n-1. For each i = 0..n-1 such that 3i != i mod n, draw an (undirected) chord from i to (3i mod n). Then a(n) is the total number of distinct chords.

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

[0, 0, 0, 2, 1, 4, 4, 6, 3, 8, 8, 10, 9, 12, 12, 14, 11, 16, 16, 18, 17, 20, 20, 22, 19, 24, 24, 26, 25, 28, 28, 30, 27, 32, 32, 34, 33, 36, 36, 38, 35, 40, 40, 42, 41, 44, 44, 46, 43, 48, 48, 50, 49, 52, 52, 54, 51, 56, 56, 58, 57, 60, 60, 62, 59, 64, 64, 66, 65, 68, 68, 70, 67, 72, 72, 74, 73, 76, 76, 78, 75, 80, 80]

cp's OEIS Frontend

A273724 Place n equally-spaced points around a circle, labeled 0,1,2,...,n-1. For each i = 0..n-1 such that 3i != i mod n, draw an (undirected) chord from i to (3i mod n). Then a(n) is the total number of distinct chords.

Table of values

List of values

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

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

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