OFFSET
1,1
LINKS
G. Everest, S. Stevens, D. Tamsett and T. Ward, Primes Generated by Recurrence Sequences, arXiv:math/0412079 [math.NT], 2004-2006.
FORMULA
a(n) ~ 10^n*log(2) as n -> infinity.
MATHEMATICA
Accumulate@Table[Length@Select[Range[10^(n - 1), 10^n - 1], FactorInteger[#][[-1, 1]] > 2*Sqrt[#] &], {n, 5}] (* or *)
lst = {}; s = -2; Do[Do[If[PrimeQ[i] || FactorInteger[i][[-1, 1]] > 2*Sqrt[i], s++], {i, 10^(n - 1), 10^n - 1}]; AppendTo[lst, s], {n, 5}]; lst
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Arkadiusz Wesolowski, Dec 11 2012
EXTENSIONS
a(9)-a(11) from Donovan Johnson, Dec 12 2012
a(12)-a(17) from Hiroaki Yamanouchi, Aug 31 2014
STATUS
approved