

A274915


Powers of odd nonFermat primes.


1



1, 7, 11, 13, 19, 23, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 263, 269, 271, 277, 281, 283, 293, 307, 311
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OFFSET

1,2


COMMENTS

n is in the sequence if n = p^m where p is in A138889 and m >= 0.  Robert Israel, Sep 15 2017
The difference between two divisors of n is never a power of 2. The first number with this property that is not in the sequence is 91.  Robert Israel, Sep 15 2017
Subsequence of A061345.


LINKS

Robert Israel, Table of n, a(n) for n = 1..10000


FORMULA

A277994(a(n)) = 0.


EXAMPLE

49 is in this sequence because 49 = 7^2 and 7 is not a Fermat prime.


MAPLE

N:= 500: # to get all terms <= N
P:= select(isprime, {seq(i, i=7..N, 2)}) minus {seq(2^i+1, i=1..ilog2(N))}:
sort(convert(map(p > seq(p^k, k=0..floor(log[p](N))), P), list)); # Robert Israel, Sep 15 2017


CROSSREFS

Cf. A019434, A061345, A092506, A138889, A277994.
Sequence in context: A092246 A084468 A292315 * A152469 A115558 A067466
Adjacent sequences: A274912 A274913 A274914 * A274916 A274917 A274918


KEYWORD

nonn,easy


AUTHOR

JuriStepan Gerasimov, Nov 11 2016


EXTENSIONS

Edited, new name, and corrected by Robert Israel, Sep 15 2017


STATUS

approved



