A356346 - cp's OEIS frontend

A356346 a(n) = Sum_{k=1..n} binomial(2k, k) phi(k), where phi is the Euler totient function.

n	a(n)
1	2
2	8
3	48
4	188
5	1196
6	3044
7	23636
8	75116
9	366836
10	1105860
11	8160180
12	18976804
13	143784004
14	384483604
15	1625423764
16	6434066884
17	43771766404
18	98222578204
19	734437326604
20	1837209557164
21	8296304050444
22	29337293687644
23	210472769694844
24	468453599159644
25	2996665727914684

[2, 8, 48, 188, 1196, 3044, 23636, 75116, 366836, 1105860, 8160180, 18976804, 143784004, 384483604, 1625423764, 6434066884, 43771766404, 98222578204, 734437326604, 1837209557164, 8296304050444, 29337293687644, 210472769694844, 468453599159644, 2996665727914684]

cp's OEIS Frontend

A356346 a(n) = Sum_{k=1..n} binomial(2k, k) phi(k), where phi is the Euler totient function.

Table of values

List of values

cp's OEIS Frontend

A356346 a(n) = Sum_{k=1..n} binomial(2*k, k) * phi(k), where phi is the Euler totient function.

Table of values

List of values

A356346 a(n) = Sum_{k=1..n} binomial(2k, k) phi(k), where phi is the Euler totient function.