OFFSET
0,2
LINKS
Max Alekseyev, Table of n, a(n) for n = 0..691
MATHEMATICA
EulerPhi[3^Range[0, 30]+1] (* Paolo Xausa, Oct 15 2023 *)
PROG
(PARI) {a(n) = eulerphi(3^n+1)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 13 2023
STATUS
approved