OFFSET
1,2
EXAMPLE
a(2)=2, since there are 2 6's in primes less than 100. Namely: 61, 67.
MATHEMATICA
Table[Count[IntegerDigits[Prime[Range[PrimePi[10^n - 1]]]], 6, 2], {n, 7}] (* Robert Price, Jun 16 2019 *)
CROSSREFS
KEYWORD
more,nonn,base
AUTHOR
Robert Price, Nov 11 2013
EXTENSIONS
a(14) from Giovanni Resta, Jul 20 2015
STATUS
approved