OFFSET
1,2
MATHEMATICA
Table[EulerPhi[4^n-1]/(2n), {n, 30}] (* Harvey P. Dale, May 01 2013 *)
PROG
(PARI) a(n) = eulerphi(4^n-1)/(2*n) \\ Felix Fröhlich, Dec 02 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Offset corrected by Sean A. Irvine, Dec 02 2019
STATUS
approved