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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 October 21 09:09 EDT 2020. Contains 337911 sequences. (Running on oeis4.)