A323780 - cp's OEIS frontend

A323780 a(n) = denominator of Sum_{d|n} (tau(d)/sigma(d)) where tau(k) = the number of the divisors of k (A000005) and sigma(k) = the sum of the divisors of k (A000203).

n	a(n)
1	1
2	3
3	2
4	21
5	3
6	2
7	4
8	105
9	26
10	9
11	6
12	7
13	7
14	12
15	1
16	3255
17	9
18	26
19	10
20	63
21	8
22	18
23	12
24	35
25	93
26	21
27	65
28	21
29	15
30	3
31	16
32	1085
33	4
34	27
35	3
36	91
37	19
38	6
39	7
40	315
41	21
42	8
43	22
44	9
45	13
46	36
47	24
48	2170
49	76
50	279
51	3
52	147
53	27
54	39
55	9
56	21
57	20
58	9
59	30
60	21
61	31
62	48
63	104
64	137795
65	21
66	12
67	34

[1, 3, 2, 21, 3, 2, 4, 105, 26, 9, 6, 7, 7, 12, 1, 3255, 9, 26, 10, 63, 8, 18, 12, 35, 93, 21, 65, 21, 15, 3, 16, 1085, 4, 27, 3, 91, 19, 6, 7, 315, 21, 8, 22, 9, 13, 36, 24, 2170, 76, 279, 3, 147, 27, 39, 9, 21, 20, 9, 30, 21, 31, 48, 104, 137795, 21, 12, 34]

cp's OEIS Frontend

A323780 a(n) = denominator of Sum_{d|n} (tau(d)/sigma(d)) where tau(k) = the number of the divisors of k (A000005) and sigma(k) = the sum of the divisors of k (A000203).

Table of values

List of values