A180772 - cp's OEIS frontend

A180772 Number of distinct solutions to the congruence x(1)*x(2) == 0 (mod n), with x() only in 1..n-1.

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	2
7	0
8	3
9	3
10	4
11	0
12	9
13	0
14	6
15	8
16	10
17	0
18	15
19	0
20	17
21	12
22	10
23	0
24	27
25	10
26	12
27	15
28	25
29	0
30	38
31	0
32	26
33	20
34	16
35	24
36	51
37	0
38	18
39	24
40	51
41	0
42	56
43	0
44	41
45	51
46	22
47	0
48	74
49	21
50	50
51	32
52	49
53	0
54	69
55	40
56	75
57	36
58	28
59	0
60	121
61	0
62	30
63	75
64	68
65	48
66	92
67	0
68	65
69	44
70	106
71	0
72	141
73	0
74	36
75	90
76	73
77	60
78	110
79	0
80	138

[0, 0, 0, 1, 0, 2, 0, 3, 3, 4, 0, 9, 0, 6, 8, 10, 0, 15, 0, 17, 12, 10, 0, 27, 10, 12, 15, 25, 0, 38, 0, 26, 20, 16, 24, 51, 0, 18, 24, 51, 0, 56, 0, 41, 51, 22, 0, 74, 21, 50, 32, 49, 0, 69, 40, 75, 36, 28, 0, 121, 0, 30, 75, 68, 48, 92, 0, 65, 44, 106, 0, 141, 0, 36, 90, 73, 60, 110, 0, 138]

cp's OEIS Frontend

A180772 Number of distinct solutions to the congruence x(1)*x(2) == 0 (mod n), with x() only in 1..n-1.

Table of values

List of values

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	2
7	0
8	3
9	3
10	4
11	0
12	9
13	0
14	6
15	8
16	10
17	0
18	15
19	0
20	17
21	12
22	10
23	0
24	27
25	10
26	12
27	15
28	25
29	0
30	38
31	0
32	26
33	20
34	16
35	24
36	51
37	0
38	18
39	24
40	51
41	0
42	56
43	0
44	41
45	51
46	22
47	0
48	74
49	21
50	50
51	32
52	49
53	0
54	69
55	40
56	75
57	36
58	28
59	0
60	121
61	0
62	30
63	75
64	68
65	48
66	92
67	0
68	65
69	44
70	106
71	0
72	141
73	0
74	36
75	90
76	73
77	60
78	110
79	0
80	138

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	2
7	0
8	3
9	3
10	4
11	0
12	9
13	0
14	6
15	8
16	10
17	0
18	15
19	0
20	17
21	12
22	10
23	0
24	27
25	10
26	12
27	15
28	25
29	0
30	38
31	0
32	26
33	20
34	16
35	24
36	51
37	0
38	18
39	24
40	51
41	0
42	56
43	0
44	41
45	51
46	22
47	0
48	74
49	21
50	50
51	32
52	49
53	0
54	69
55	40
56	75
57	36
58	28
59	0
60	121
61	0
62	30
63	75
64	68
65	48
66	92
67	0
68	65
69	44
70	106
71	0
72	141
73	0
74	36
75	90
76	73
77	60
78	110
79	0
80	138

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	2
7	0
8	3
9	3
10	4
11	0
12	9
13	0
14	6
15	8
16	10
17	0
18	15
19	0
20	17
21	12
22	10
23	0
24	27
25	10
26	12
27	15
28	25
29	0
30	38
31	0
32	26
33	20
34	16
35	24
36	51
37	0
38	18
39	24
40	51
41	0
42	56
43	0
44	41
45	51
46	22
47	0
48	74
49	21
50	50
51	32
52	49
53	0
54	69
55	40
56	75
57	36
58	28
59	0
60	121
61	0
62	30
63	75
64	68
65	48
66	92
67	0
68	65
69	44
70	106
71	0
72	141
73	0
74	36
75	90
76	73
77	60
78	110
79	0
80	138