OFFSET
0,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..100
MAPLE
with(numtheory): seq(`if`(n=0, 1, phi(9^n-1)/n), n=0..22);
MATHEMATICA
Join[{1}, Array[EulerPhi[9^# - 1]/# &, 25]] (* Paolo Xausa, Jun 17 2024 *)
PROG
(PARI) a(n) = if(n==0, 1, eulerphi(9^n-1)/n) \\ Andrew Howroyd, Feb 01 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(20) onwards from Andrew Howroyd, Feb 01 2024
STATUS
approved