OFFSET
1,1
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..100
Eric Weisstein's World of Mathematics, Totient Function.
Wikipedia, Euler's totient function.
MATHEMATICA
Array[EulerPhi[6^# - 1]/# &, 25] (* Paolo Xausa, Jun 17 2024 *)
PROG
(PARI) {a(n) = eulerphi(6^n-1)/n}
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Nov 22 2017
STATUS
approved