A356339 - cp's OEIS frontend

A356339 a(n) = Sum_{k=1..n} binomial(2n, n-k) sigma_2(k).

n	a(n)
1	1
2	9
3	55
4	297
5	1496
6	7215
7	33783
8	154825
9	698077
10	3107424
11	13690161
12	59802471
13	259377080
14	1118176887
15	4795381640
16	20472223529
17	87051685546
18	368857919085
19	1558036408998
20	6562564601592
21	27571934249754
22	115574440020477
23	483444570596465
24	2018365519396135
25	8411811012694246

[1, 9, 55, 297, 1496, 7215, 33783, 154825, 698077, 3107424, 13690161, 59802471, 259377080, 1118176887, 4795381640, 20472223529, 87051685546, 368857919085, 1558036408998, 6562564601592, 27571934249754, 115574440020477, 483444570596465, 2018365519396135, 8411811012694246]

cp's OEIS Frontend

A356339 a(n) = Sum_{k=1..n} binomial(2n, n-k) sigma_2(k).

Table of values

List of values

cp's OEIS Frontend

A356339 a(n) = Sum_{k=1..n} binomial(2*n, n-k) * sigma_2(k).

Table of values

List of values

A356339 a(n) = Sum_{k=1..n} binomial(2n, n-k) sigma_2(k).