A087530 Primes consisting only of digits 3 and 5 occurring with equal frequency.

53, 35553533, 53355353, 53533553, 3335553553, 3355335553, 3355355533, 3355533553, 3355535353, 3535355353, 3553535353, 3553555333, 3555353353, 3555353533, 3555533533, 5353353553, 5353533553, 5353553533, 5355353533, 5355533353, 5533553353, 5535535333

Offset: 1

Author

Amarnath Murthy and Paul D. Hanna, Sep 12 2003

Keywords

• base
• nonn

Comments

There are 18 digit pairs which can produce such primes. (1,0),(1,3),(1,4),(1,6),(1,7),(1,9),(2,3),(2,9),(3,4),(3,5),(3,7),(3,8),(4,7),(4,9),(5,9),(6,7),(7,9),(8,9).

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A087510, A087511, A087529.

Programs

Mathematica

Sort[Select[FromDigits/@Flatten[Permutations/@Table[PadRight[{},2n,{3,5}],{n,5}],1],PrimeQ]] (* Harvey P. Dale, Oct 24 2012 *)

PARI

\\ Needs B() from A087510.
concat(vector(6,k,B(k,3,5,isprime))) \\ Andrew Howroyd, Sep 20 2024

Extensions

Edited by Charles R Greathouse IV, Oct 28 2009