|
%I #14 Jul 21 2015 06:47:18
%S 0,6,60,542,4826,43359,397093,3677641,34316162,321993007,3035059323,
%T 28710966351,272413818120,2591276923548
%N Number of primes less than 10^n having at least one digit 9.
%e a(2) = 6 because of the 25 primes less than 10^2, 6 have at least one digit 9.
%t 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], 9] != {}, c++ ]]; Print[c]; p--, {n, 1, 8}] (* _Robert G. Wilson v_, Feb 02 2004 *)
%Y a(n) + A091643(n) = A006880(n).
%Y Cf. A091644, A091645, A091646, A091647, A090705, A090706, A091707, A091708, A091709.
%K nonn,base
%O 1,2
%A _Enoch Haga_, Jan 30 2004
%E Edited and extended by _Robert G. Wilson v_, Feb 02 2004
%E 3 more terms from _Ryan Propper_, Aug 22 2005
%E a(13) from _Robert Price_, Nov 11 2013
%E a(14) from _Giovanni Resta_, Jul 21 2015
|
