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

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.

Cf. A000010, A011755.

Sequence in context: A194945 A093651 A181420 * A254680 A018411 A083989

Adjacent sequences: A333288 A333289 A333290 * A333292 A333293 A333294

Keyword

nonn,look

Author

N. J. A. Sloane, Mar 22 2020

Status

approved