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A227533 Smallest e > 1 such that (2n)^e is a totient, or 0 if no such e exists. 4
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, 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, 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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Conjecture: a(n) > 0 for all n.

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..100000

Charles R Greathouse IV, GP script for efficiently computing the sequence

EXAMPLE

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.

PROG

(PARI) a(n)=my(k=2); while(!istotient((2*n)^k), k++); k

CROSSREFS

Cf. A000010, A002202, A065528, A227534, A227535.

Sequence in context: A103379 A032550 A036450 * A235124 A235125 A238418

Adjacent sequences:  A227530 A227531 A227532 * A227534 A227535 A227536

KEYWORD

nonn

AUTHOR

Charles R Greathouse IV, Jul 14 2013

STATUS

approved

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Last modified January 17 22:44 EST 2019. Contains 319251 sequences. (Running on oeis4.)