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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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 25 11:55 EDT 2017. Contains 288710 sequences.