A117272 - OEIS

A117272

Prime numbers p for which none of its digits appear in the decimal expansion of p/pi(p).

3, 5, 11, 19, 47, 61, 71, 97, 157, 179, 229, 373, 409, 691, 1231, 1373, 1987, 2213, 2557, 3119, 3989, 8443, 9311, 17191, 20707, 26261, 38281, 41381, 48611, 54541, 66889, 74257, 255709

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..33.

EXAMPLE

373 is in the sequence because 1) it is a prime number, 2) there are 74 prime numbers smaller than or equal to 373, 3) in the decimal expansion of 373/74=5.04(054)... there are no 3's and 7's.

MATHEMATICA

fQ[n_] := Block[{p = Prime@n}, Intersection[ Union@ Flatten@ RealDigits[p/n][[1]], IntegerDigits@ p] == {}]; Do[ If[fQ@n, Print@ Prime@n], {n, 200000}] (* Robert G. Wilson v, Apr 24 2006 *)

CROSSREFS

Cf. A000720: pi(n), the number of primes <= n.

Sequence in context: A045961 A293820 A281380 * A243616 A147189 A118744

Adjacent sequences: A117269 A117270 A117271 * A117273 A117274 A117275

KEYWORD

base,more,nonn

AUTHOR

Luc Stevens (lms022(AT)yahoo.com), Apr 23 2006

EXTENSIONS

Edited, corrected and extended by Robert G. Wilson v, Apr 24 2006

STATUS

approved