A091710 Number of primes less than 10^n having at least one digit 9.

0, 6, 60, 542, 4826, 43359, 397093, 3677641, 34316162, 321993007, 3035059323, 28710966351, 272413818120, 2591276923548

Offset

1,2

Links

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

Example

a(2) = 6 because of the 25 primes less than 10^2, 6 have at least one digit 9.

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], 9] != {}, c++ ]]; Print[c]; p--, {n, 1, 8}] (* Robert G. Wilson v, Feb 02 2004 *)

Crossrefs

a(n) + A091643(n) = A006880(n).

Cf. A091644, A091645, A091646, A091647, A090705, A090706, A091707, A091708, A091709.

Sequence in context: A102232 A121113 A213269 * A054880 A186656 A122653

Adjacent sequences: A091707 A091708 A091709 * A091711 A091712 A091713

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 22 2005

a(13) from Robert Price, Nov 11 2013

a(14) from Giovanni Resta, Jul 21 2015

Status

approved