A333291 - OEIS

A333291

a(n) = Sum_{i=1..n, gcd(i,n)=1} i*phi(i) where phi is Euler's totient function A000010.

1, 1, 3, 7, 17, 21, 49, 69, 105, 103, 217, 173, 375, 347, 435, 509, 863, 601, 1243, 983, 1271, 1265, 2217, 1449, 2575, 2225, 2935, 2573, 4549, 2241, 5601, 4609, 5195, 4997, 6453, 4531, 9519, 7099, 8457, 6897, 13111, 6621, 15255, 11053, 11691, 12397, 20033, 11471, 20905, 14563, 19307, 17663, 28901, 16285, 26119

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OFFSET

1,3

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..10000

MAPLE

a:= n-> add(`if`(igcd(i, n)=1, i*numtheory[phi](i), 0), i=1..n):

seq(a(n), n=1..55); # Alois P. Heinz, Mar 22 2020

PROG

(PARI) a(n) = sum(i=1, n, if (gcd(n, i) == 1, i*eulerphi(i))); \\ Michel Marcus, Mar 23 2020

CROSSREFS

Suggested by A023896 and A319087.