A176789 - cp's OEIS frontend

A176789 a(n) = (0!! - 1!! + 2!! - 3!! + ... + (-1)^(n-1)*(n-1)!!) mod n.

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

[0, 0, 2, 3, 2, 4, 5, 7, 4, 4, 2, 7, 3, 0, 4, 3, 5, 10, 3, 19, 7, 4, 3, 7, 14, 0, 10, 7, 5, 4, 29, 11, 4, 6, 14, 19, 4, 26, 13, 39, 13, 28, 2, 15, 19, 20, 11, 19, 14, 14, 40, 39, 0, 10, 4, 7, 7, 8, 7, 19, 26, 38, 28, 27, 39, 4, 57, 23, 43, 14, 5, 55, 30, 6, 64, 7, 70, 52, 50, 19, 37, 10, 75, 7]

cp's OEIS Frontend

A176789 a(n) = (0!! - 1!! + 2!! - 3!! + ... + (-1)^(n-1)*(n-1)!!) mod n.

Table of values

List of values

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

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

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