login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A274915 Powers of odd non-Fermat 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 (list; graph; refs; listen; history; text; internal format)
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

Juri-Stepan Gerasimov, Nov 11 2016

EXTENSIONS

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

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 6 15:48 EDT 2020. Contains 334828 sequences. (Running on oeis4.)