A181861 - cp's OEIS frontend

A181861 a(n) = gcd(n^2, n!/floor(n/2)!^2).

n	a(n)
0	1
1	1
2	2
3	3
4	2
5	5
6	4
7	7
8	2
9	9
10	4
11	11
12	12
13	13
14	4
15	45
16	2
17	17
18	4
19	19
20	4
21	21
22	4
23	23
24	4
25	25
26	4
27	27
28	8
29	29
30	180
31	31
32	2
33	99
34	4
35	175
36	12
37	37
38	4
39	117
40	20
41	41
42	12
43	43
44	8
45	675
46	4
47	47
48	36
49	49
50	4
51	153
52	8
53	53
54	4
55	55
56	56
57	57
58	4
59	59
60	16

[1, 1, 2, 3, 2, 5, 4, 7, 2, 9, 4, 11, 12, 13, 4, 45, 2, 17, 4, 19, 4, 21, 4, 23, 4, 25, 4, 27, 8, 29, 180, 31, 2, 99, 4, 175, 12, 37, 4, 117, 20, 41, 12, 43, 8, 675, 4, 47, 36, 49, 4, 153, 8, 53, 4, 55, 56, 57, 4, 59, 16]

cp's OEIS Frontend

A181861 a(n) = gcd(n^2, n!/floor(n/2)!^2).

Table of values

List of values

n	a(n)
0	1
1	1
2	2
3	3
4	2
5	5
6	4
7	7
8	2
9	9
10	4
11	11
12	12
13	13
14	4
15	45
16	2
17	17
18	4
19	19
20	4
21	21
22	4
23	23
24	4
25	25
26	4
27	27
28	8
29	29
30	180
31	31
32	2
33	99
34	4
35	175
36	12
37	37
38	4
39	117
40	20
41	41
42	12
43	43
44	8
45	675
46	4
47	47
48	36
49	49
50	4
51	153
52	8
53	53
54	4
55	55
56	56
57	57
58	4
59	59
60	16

n	a(n)
0	1
1	1
2	2
3	3
4	2
5	5
6	4
7	7
8	2
9	9
10	4
11	11
12	12
13	13
14	4
15	45
16	2
17	17
18	4
19	19
20	4
21	21
22	4
23	23
24	4
25	25
26	4
27	27
28	8
29	29
30	180
31	31
32	2
33	99
34	4
35	175
36	12
37	37
38	4
39	117
40	20
41	41
42	12
43	43
44	8
45	675
46	4
47	47
48	36
49	49
50	4
51	153
52	8
53	53
54	4
55	55
56	56
57	57
58	4
59	59
60	16

n	a(n)
0	1
1	1
2	2
3	3
4	2
5	5
6	4
7	7
8	2
9	9
10	4
11	11
12	12
13	13
14	4
15	45
16	2
17	17
18	4
19	19
20	4
21	21
22	4
23	23
24	4
25	25
26	4
27	27
28	8
29	29
30	180
31	31
32	2
33	99
34	4
35	175
36	12
37	37
38	4
39	117
40	20
41	41
42	12
43	43
44	8
45	675
46	4
47	47
48	36
49	49
50	4
51	153
52	8
53	53
54	4
55	55
56	56
57	57
58	4
59	59
60	16