A080381 - cp's OEIS frontend

A080381 Triangle read by rows: gcd(binomial(n,floor(n/2)), binomial(n,i)), i=0..n; greatest common divisor of binomial coefficients and corresponding central binomial coefficient.

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	1
6	1
7	3
8	3
9	1
10	1
11	2
12	6
13	2
14	1
15	1
16	5
17	10
18	10
19	5
20	1
21	1
22	2
23	5
24	20
25	5
26	2
27	1
28	1
29	7
30	7
31	35
32	35
33	7
34	7
35	1
36	1
37	2
38	14
39	14
40	70
41	14
42	14
43	2
44	1
45	1
46	9
47	18
48	42
49	126
50	126
51	42
52	18
53	9
54	1
55	1
56	2
57	9
58	12
59	42
60	252
61	42
62	12
63	9
64	2
65	1
66	1
67	11
68	11
69	33
70	66
71	462
72	462
73	66
74	33
75	11
76	11
77	1
78	1
79	12
80	66
81	44
82	33
83	132
84	924
85	132
86	33
87	44
88	66
89	12
90	1

[1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 2, 6, 2, 1, 1, 5, 10, 10, 5, 1, 1, 2, 5, 20, 5, 2, 1, 1, 7, 7, 35, 35, 7, 7, 1, 1, 2, 14, 14, 70, 14, 14, 2, 1, 1, 9, 18, 42, 126, 126, 42, 18, 9, 1, 1, 2, 9, 12, 42, 252, 42, 12, 9, 2, 1, 1, 11, 11, 33, 66, 462, 462, 66, 33, 11, 11, 1, 1, 12, 66, 44, 33, 132, 924, 132, 33, 44, 66, 12, 1]

cp's OEIS Frontend

A080381 Triangle read by rows: gcd(binomial(n,floor(n/2)), binomial(n,i)), i=0..n; greatest common divisor of binomial coefficients and corresponding central binomial coefficient.

Table of values

List of values

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	1
6	1
7	3
8	3
9	1
10	1
11	2
12	6
13	2
14	1
15	1
16	5
17	10
18	10
19	5
20	1
21	1
22	2
23	5
24	20
25	5
26	2
27	1
28	1
29	7
30	7
31	35
32	35
33	7
34	7
35	1
36	1
37	2
38	14
39	14
40	70
41	14
42	14
43	2
44	1
45	1
46	9
47	18
48	42
49	126
50	126
51	42
52	18
53	9
54	1
55	1
56	2
57	9
58	12
59	42
60	252
61	42
62	12
63	9
64	2
65	1
66	1
67	11
68	11
69	33
70	66
71	462
72	462
73	66
74	33
75	11
76	11
77	1
78	1
79	12
80	66
81	44
82	33
83	132
84	924
85	132
86	33
87	44
88	66
89	12
90	1

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	1
6	1
7	3
8	3
9	1
10	1
11	2
12	6
13	2
14	1
15	1
16	5
17	10
18	10
19	5
20	1
21	1
22	2
23	5
24	20
25	5
26	2
27	1
28	1
29	7
30	7
31	35
32	35
33	7
34	7
35	1
36	1
37	2
38	14
39	14
40	70
41	14
42	14
43	2
44	1
45	1
46	9
47	18
48	42
49	126
50	126
51	42
52	18
53	9
54	1
55	1
56	2
57	9
58	12
59	42
60	252
61	42
62	12
63	9
64	2
65	1
66	1
67	11
68	11
69	33
70	66
71	462
72	462
73	66
74	33
75	11
76	11
77	1
78	1
79	12
80	66
81	44
82	33
83	132
84	924
85	132
86	33
87	44
88	66
89	12
90	1

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	1
6	1
7	3
8	3
9	1
10	1
11	2
12	6
13	2
14	1
15	1
16	5
17	10
18	10
19	5
20	1
21	1
22	2
23	5
24	20
25	5
26	2
27	1
28	1
29	7
30	7
31	35
32	35
33	7
34	7
35	1
36	1
37	2
38	14
39	14
40	70
41	14
42	14
43	2
44	1
45	1
46	9
47	18
48	42
49	126
50	126
51	42
52	18
53	9
54	1
55	1
56	2
57	9
58	12
59	42
60	252
61	42
62	12
63	9
64	2
65	1
66	1
67	11
68	11
69	33
70	66
71	462
72	462
73	66
74	33
75	11
76	11
77	1
78	1
79	12
80	66
81	44
82	33
83	132
84	924
85	132
86	33
87	44
88	66
89	12
90	1