%I A091640
%S A091640 4,23,136,897,6367,46706,355148,2770239,21984207,176966593,1440765209,
%T A091640 11838096715
%N A091640 Number of primes less than 10^n which do not contain the digit 6.
%F A091640 Number of primes less than 10^n after removing any primes with at least 
               one digit 6.
%e A091640 a(2) = 23 because of the 25 primes less than 10^2, 2 have at least one 
               digit 6; 25-2 = 23.
%t A091640 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}] (from Robert G. Wilson 
               v Feb 02 2004)
%Y A091640 a(n) + A091707(n) = A006880(n).
%Y A091640 Cf. A091634, A091635, A091636, A091637, A091638, A091639, A091641, A091642, 
               A091643.
%Y A091640 Sequence in context: A144465 A024050 A038723 this_sequence A067110 A158197 
               A038736
%Y A091640 Adjacent sequences: A091637 A091638 A091639 this_sequence A091641 A091642 
               A091643
%K A091640 more,nonn,base
%O A091640 1,1
%A A091640 Enoch Haga (Enokh(AT)comcast.net), Jan 30 2004
%E A091640 Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 02 
               2004
%E A091640 a(9)-a(12) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 14 
               2008