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!)
A215962 Number of primes of the form 1 + b^16384 for 1 < b < 10^n. 0
0, 0, 0, 0, 1, 33, 137 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,6
COMMENTS
Primes 1 + b^16384 are a form of generalized Fermat primes.
It is conjectured that a(n) is asymptotic to 0.000488872*li(10^n)
LINKS
EXAMPLE
a(5) = 1 because the generalized Fermat numbers F_14(b) where b<10^5 are prime only for b = 67234.
PROG
(PARI) a(n) = sum(b=1, 10^n/2-1, isprime((2*b)^16384+1))
CROSSREFS
Sequence in context: A158588 A232538 A231758 * A084028 A283552 A007260
KEYWORD
nonn
AUTHOR
Henryk Dabrowski, Aug 29 2012
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 07:27 EDT 2024. Contains 371265 sequences. (Running on oeis4.)