

A091707


Number of primes less than 10^n having at least one digit 6.


10



0, 2, 32, 332, 3225, 31792, 309431, 2991216, 28863327, 278085918, 2677289604, 25769815303, 248050788931, 2388172543971
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..14.


EXAMPLE

a(1) = 0 because of the 4 primes less than 10^1, none have at least one digit 6.


MATHEMATICA

NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; c = 0; p = 1; Do[ While[ p = NextPrim[p]; p < 10^n, If[ Position[ IntegerDigits[p], 6] != {}, c++ ]]; Print[c]; p, {n, 1, 8}] (* Robert G. Wilson v, Feb 02 2004 *)


CROSSREFS

a(n) + A091640(n) = A006880(n).
Cf. A091644, A091645, A091646, A091647, A091705, A091706, A091708, A091709, A091710.
Sequence in context: A079766 A224293 A053065 * A060868 A270445 A199019
Adjacent sequences: A091704 A091705 A091706 * A091708 A091709 A091710


KEYWORD

nonn,base


AUTHOR

Enoch Haga, Jan 30 2004


EXTENSIONS

Edited and extended by Robert G. Wilson v, Feb 02 2004
3 more terms from Ryan Propper, Aug 21 2005
a(13) from Robert Price, Nov 11 2013
a(14) from Giovanni Resta, Jul 21 2015


STATUS

approved



