A385147 a(n) = Sum_{i=1..n} 2^phi(i), where phi=A000010.

2, 4, 8, 12, 28, 32, 96, 112, 176, 192, 1216, 1232, 5328, 5392, 5648, 5904, 71440, 71504, 333648, 333904, 338000, 339024, 4533328, 4533584, 5582160, 5586256, 5848400, 5852496, 274287952, 274288208, 1348030032, 1348095568, 1349144144, 1349209680, 1365986896, 1365990992

Offset: 1

Author

Hunter Yeoman, Jun 19 2025

Keywords

• nonn
• easy

Crossrefs

Cf. A000010.

Partial sums of A066781.

Programs

Mathematica

Accumulate[Table[2^EulerPhi[n], {n, 1, 36}]] (* Amiram Eldar, Jun 28 2025 *)

PARI

a(n) = sum(i=1, n, 2^eulerphi(i)); \\ Michel Marcus, Jun 27 2025

Python

from sympy import totient
a = 0
terms = []
for i in range(1, 36):
    a += 2 ** totient(i)
    terms.append(str(a))
print(", ".join(terms))