0,2

with(numtheory): phi(4^n-1)/n;

Sequence in context: A148193 A002528 A148194 this_sequence A148195 A005028 A148196

Adjacent sequences: A027692 A027693 A027694 this_sequence A027696 A027697 A027698

nonn

N. J. A. Sloane (njas(AT)research.att.com).