OFFSET
0,2
LINKS
Max Alekseyev, Table of n, a(n) for n = 0..561
FORMULA
a(n) = A053285(2*n). - Max Alekseyev, Jan 08 2024
MATHEMATICA
EulerPhi[4^Range[0, 30]+1] (* Paolo Xausa, Oct 14 2023 *)
PROG
(PARI) {a(n) = eulerphi(4^n+1)}
(Python)
from sympy import totient
def A366608(n): return totient((1<<(n<<1))+1) # Chai Wah Wu, Oct 14 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 14 2023
STATUS
approved