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
Yves Gallot, How many prime numbers appear in a sequence ?
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/2-1, isprime((2*b)^8192+1))
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Henryk Dabrowski, Aug 29 2012
STATUS
approved