A036941 Smallest n-digit prime containing only digits 3 and 5, or 0 if no such prime exists.

3, 53, 353, 3533, 33353, 333533, 3335533, 33335333, 333535333, 3333353533, 33333353533, 333333533353, 3333333353353, 33333333555553, 333333333353353, 3333333333333533, 33333333333355333, 333333333333353533

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..990

Maple

A:= proc(n) local j, x, t;
  x:= (10^n-1)/3;
  for t from 1 to 2^n do
    if isprime(x) then return x fi;
    j:= padic:-ordp(t, 2);
    x:= x  - (x mod 10^j) + (7 * 10^j-1)/3;
  od:
  0
end proc:
seq(A(n), n=1..100); # Robert Israel, Apr 22 2016

Mathematica

Table[SelectFirst[FromDigits/@(Join[#, {3}]&/@Tuples[{3, 5}, n]), PrimeQ], {n, 0, 20}](* The program uses the SelectFirst function from Mathematica version 10 *) (* Harvey P. Dale, Oct 07 2014 *)

Crossrefs

Cf. A036229, A020462, A036315.

Sequence in context: A141929 A216042 A292530 * A215435 A121504 A099665

Adjacent sequences: A036938 A036939 A036940 * A036942 A036943 A036944

Keyword

nonn,base

Author

Patrick De Geest, Jan 04 1999

Status

approved