This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A091634 Number of primes less than 10^n which do not contain the digit 0. 30
 4, 25, 153, 1010, 7122, 52313, 397866, 3103348, 24649318, 198536215, 1616808581, 13287264748, 110033428309, 917072930187 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA Number of primes less than 10^n after removing any primes with at least one digit 0. a(n) <= A052386(n) = 9*(9^n-1)/8. - Charles R Greathouse IV, Sep 13 2016 a(n) <= (9^n-1)/2 = A052386(n)*4/9 since the last digit of a prime of n digits can only be one of 4 numbers, (2,3,5,7) when n = 1 and (1,3,7,9) when n > 1. - Chai Wah Wu, Mar 18 2018 EXAMPLE a(3) = 153 because there are 168 primes less than 10^3, 15 primes have at least one zero; 168 - 15 = 153. 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], 0] == {}, c++ ]]; Print[c]; p--, {n, 1, 8}] (* Robert G. Wilson v, Feb 02 2004 *) CROSSREFS a(n) + A091644(n) = A006880(n). Cf. A091635, A091636, A091637, A091638, A091639, A091640, A091641, A091642, A091643. Sequence in context: A302064 A221849 A055846 * A236580 A010909 A079750 Adjacent sequences:  A091631 A091632 A091633 * A091635 A091636 A091637 KEYWORD more,nonn,base AUTHOR Enoch Haga, Jan 30 2004 EXTENSIONS Edited and extended by Robert G. Wilson v, Feb 02 2004 a(9)-a(12) from Donovan Johnson, Feb 14 2008 a(13) from Robert Price, Nov 08 2013 a(14) from Giovanni Resta, Mar 20 2017 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 17 14:47 EDT 2019. Contains 328114 sequences. (Running on oeis4.)