login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A228845 Least m such that (2k+1)*2^m + 1 is a prime factor of the Fermat number 2^(2^n) + 1. 2
1, 2, 4, 8, 16, 7, 8, 9, 11, 11, 12, 13, 14 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
a(n) >= n + 2 for n >= 2.
a(n) = A228846(n) if 2^(2^n) + 1 is prime or semiprime.
LINKS
Wilfrid Keller, Fermat factoring status
Eric Weisstein's World of Mathematics, Fermat Number
CROSSREFS
Sequence in context: A212638 A016018 A333492 * A228846 A070336 A348433
KEYWORD
nonn,hard,more
AUTHOR
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 05:48 EDT 2024. Contains 371265 sequences. (Running on oeis4.)