OFFSET
1,2
COMMENTS
Primes 1 + b^32 are a form of generalized Fermat primes.
It is conjectured that a(n) is asymptotic to 0.112903*li(10^n).
LINKS
Yves Gallot, How many prime numbers appear in a sequence ?
FORMULA
a(n) = A214956(32*n) - 1.
EXAMPLE
a(2) = 3 because the Fermat numbers F_5(b) where b<10^2 are prime only for b = 30, 54, 96.
MATHEMATICA
Table[Length[Select[Range[2, 10^n-1]^32 + 1, PrimeQ]], {n, 4}] (* T. D. Noe, Aug 01 2012 *)
PROG
(PARI) a(n) = sum(b=1, 10^n/2-1, isprime((2*b)^32+1))
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Henryk Dabrowski, Aug 01 2012
EXTENSIONS
a(9)-a(10) from Chai Wah Wu, Oct 18 2018
STATUS
approved