cp's OEIS Frontend

A227533 Smallest e > 1 such that (2n)^e is a totient, or 0 if no such e exists.

%I A227533 #12 Jul 19 2013 09:12:54
%S A227533 2,2,2,2,2,2,2,2,2,2,3,2,2,2,2,2,4,2,3,2,2,2,4,2,2,2,2,2,3,2,5,2,2,2,
%T A227533 2,2,2,3,3,2,4,2,15,2,2,4,2,2,3,2,3,2,4,2,2,2,2,2,3,2,7,2,2,2,2,2,2,2,
%U A227533 4,2,3,2,2,2,2,3,3,2,8,2,2,4,15,2,2,3,2,2,5,2,4,2,2
%N A227533 Smallest e > 1 such that (2n)^e is a totient, or 0 if no such e exists.
%C A227533 Conjecture: a(n) > 0 for all n.
%H A227533 Charles R Greathouse IV, <a href="/A227533/b227533.txt">Table of n, a(n) for n = 1..100000</a>
%H A227533 Charles R Greathouse IV, <a href="/A227533/a227533.gp.txt">GP script for efficiently computing the sequence</a>
%e A227533 a(1) = 2 because phi(5) = 2^2. a(11) = 3 because phi(13315) = 22^3 but phi(k) is not equal to 22^2 for any k.
%o A227533 (PARI) a(n)=my(k=2);while(!istotient((2*n)^k),k++);k
%Y A227533 Cf. A000010, A002202, A065528, A227534, A227535.
%K A227533 nonn
%O A227533 1,1
%A A227533 _Charles R Greathouse IV_, Jul 14 2013