

A215961


Number of primes of the form 1 + b^8192 for 1 < b < 10^n.


0




OFFSET

1,5


COMMENTS

Primes 1 + b^8192 are a form of generalized Fermat primes. It is conjectured that a(n) is asymptotic to 0.00103368*li(10^n).


LINKS



EXAMPLE

a(5) = 3 because the generalized Fermat numbers F_13(b) where b<10^5 are prime only for b = 30406, 71852, 85654.


PROG

(PARI) a(n) = sum(b=1, 10^n/21, isprime((2*b)^8192+1))


CROSSREFS



KEYWORD

nonn,more


AUTHOR



STATUS

approved



