A301556 - cp's OEIS frontend

A301556 Expansion of Product_{k>=1} ((1 + x^k)/(1 - x^k))^(sigma_2(k)).

n	a(n)
0	1
1	2
2	12
3	42
4	154
5	498
6	1640
7	4990
8	15092
9	43840
10	125220
11	348478
12	954294
13	2561714
14	6776404
15	17644494
16	45338734
17	114971434
18	288148860
19	713968998
20	1750662814
21	4249685398
22	10219662844
23	24356466418
24	57558783492
25	134922807056
26	313842321696
27	724651728916

[1, 2, 12, 42, 154, 498, 1640, 4990, 15092, 43840, 125220, 348478, 954294, 2561714, 6776404, 17644494, 45338734, 114971434, 288148860, 713968998, 1750662814, 4249685398, 10219662844, 24356466418, 57558783492, 134922807056, 313842321696, 724651728916]

cp's OEIS Frontend

A301556 Expansion of Product_{k>=1} ((1 + x^k)/(1 - x^k))^(sigma_2(k)).

Table of values

List of values