OFFSET
0,2
LINKS
Max Alekseyev, Table of n, a(n) for n = 0..502
FORMULA
a(n) = A053285(3*n). - Max Alekseyev, Jan 09 2024
MATHEMATICA
EulerPhi[8^Range[0, 21] + 1] (* Paul F. Marrero Romero, Oct 17 2023 *)
PROG
(PARI) {a(n) = eulerphi(8^n+1)}
(Python)
from sympy import totient
def A366658(n): return totient((1<<3*n)+1) # Chai Wah Wu, Oct 15 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 15 2023
STATUS
approved