A356343 - cp's OEIS frontend

A356343 a(n) = Sum_{k=1..n} binomial(2n, k) phi(k), where phi is the Euler totient function.

n	a(n)
1	2
2	10
3	61
4	288
5	1723
6	6524
7	37441
8	158504
9	737019
10	2867500
11	15200293
12	56951428
13	291648771
14	1141099348
15	4686310739
16	19016248192
17	95307214595
18	358297247772
19	1748879020425
20	6725041736572
21	27649247188159
22	108460437728204
23	522912325647543
24	1966622896068784
25	8831400010510925

[2, 10, 61, 288, 1723, 6524, 37441, 158504, 737019, 2867500, 15200293, 56951428, 291648771, 1141099348, 4686310739, 19016248192, 95307214595, 358297247772, 1748879020425, 6725041736572, 27649247188159, 108460437728204, 522912325647543, 1966622896068784, 8831400010510925]

cp's OEIS Frontend

A356343 a(n) = Sum_{k=1..n} binomial(2n, k) phi(k), where phi is the Euler totient function.

Table of values

List of values

cp's OEIS Frontend

A356343 a(n) = Sum_{k=1..n} binomial(2*n, k) * phi(k), where phi is the Euler totient function.

Table of values

List of values

A356343 a(n) = Sum_{k=1..n} binomial(2n, k) phi(k), where phi is the Euler totient function.