A175386 - cp's OEIS frontend

A175386 a(n) = denominator of sum((1/i)*C(2n-i-1,i-1),i=1..n).

n	a(n)
1	1
2	2
3	6
4	4
5	5
6	4
7	7
8	8
9	18
10	10
11	11
12	24
13	13
14	14
15	30
16	16
17	17
18	12
19	19
20	20
21	42
22	22
23	23
24	48
25	25
26	26
27	54
28	28
29	29
30	20
31	31
32	32
33	66
34	34
35	35
36	72
37	37
38	38
39	78
40	40
41	41
42	28
43	43
44	44
45	90
46	46
47	47
48	96
49	49
50	50
51	6
52	52
53	53
54	36
55	55
56	56
57	114
58	58
59	59
60	120
61	61
62	62
63	126
64	64
65	65
66	44
67	67
68	68
69	138
70	70
71	71

[1, 2, 6, 4, 5, 4, 7, 8, 18, 10, 11, 24, 13, 14, 30, 16, 17, 12, 19, 20, 42, 22, 23, 48, 25, 26, 54, 28, 29, 20, 31, 32, 66, 34, 35, 72, 37, 38, 78, 40, 41, 28, 43, 44, 90, 46, 47, 96, 49, 50, 6, 52, 53, 36, 55, 56, 114, 58, 59, 120, 61, 62, 126, 64, 65, 44, 67, 68, 138, 70, 71]

cp's OEIS Frontend

A175386 a(n) = denominator of sum((1/i)*C(2n-i-1,i-1),i=1..n).

Table of values

List of values

n	a(n)
1	1
2	2
3	6
4	4
5	5
6	4
7	7
8	8
9	18
10	10
11	11
12	24
13	13
14	14
15	30
16	16
17	17
18	12
19	19
20	20
21	42
22	22
23	23
24	48
25	25
26	26
27	54
28	28
29	29
30	20
31	31
32	32
33	66
34	34
35	35
36	72
37	37
38	38
39	78
40	40
41	41
42	28
43	43
44	44
45	90
46	46
47	47
48	96
49	49
50	50
51	6
52	52
53	53
54	36
55	55
56	56
57	114
58	58
59	59
60	120
61	61
62	62
63	126
64	64
65	65
66	44
67	67
68	68
69	138
70	70
71	71

n	a(n)
1	1
2	2
3	6
4	4
5	5
6	4
7	7
8	8
9	18
10	10
11	11
12	24
13	13
14	14
15	30
16	16
17	17
18	12
19	19
20	20
21	42
22	22
23	23
24	48
25	25
26	26
27	54
28	28
29	29
30	20
31	31
32	32
33	66
34	34
35	35
36	72
37	37
38	38
39	78
40	40
41	41
42	28
43	43
44	44
45	90
46	46
47	47
48	96
49	49
50	50
51	6
52	52
53	53
54	36
55	55
56	56
57	114
58	58
59	59
60	120
61	61
62	62
63	126
64	64
65	65
66	44
67	67
68	68
69	138
70	70
71	71

n	a(n)
1	1
2	2
3	6
4	4
5	5
6	4
7	7
8	8
9	18
10	10
11	11
12	24
13	13
14	14
15	30
16	16
17	17
18	12
19	19
20	20
21	42
22	22
23	23
24	48
25	25
26	26
27	54
28	28
29	29
30	20
31	31
32	32
33	66
34	34
35	35
36	72
37	37
38	38
39	78
40	40
41	41
42	28
43	43
44	44
45	90
46	46
47	47
48	96
49	49
50	50
51	6
52	52
53	53
54	36
55	55
56	56
57	114
58	58
59	59
60	120
61	61
62	62
63	126
64	64
65	65
66	44
67	67
68	68
69	138
70	70
71	71