A087529 Primes consisting only of digits 3 and 4 occurring with equal frequency.

43, 34434343, 44334343, 44343433, 3334344443, 3343443443, 3344334443, 3344344343, 3344434433, 3433434443, 3433444433, 3434444333, 3443343443, 3444334343, 4334433443, 4334443433, 4343444333, 4344333443, 4344433343, 4344443333, 4433343443, 4433344343, 4434334343

Offset: 1

Author

Paul D. Hanna and Amarnath Murthy, 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, A087528.

Programs

Mathematica

Select[FromDigits/@Flatten[Permutations/@Table[PadRight[{},2n,{4,3}],{n,5}],1],PrimeQ]//Sort (* Harvey P. Dale, Aug 08 2017 *)

PARI

\\ Needs B() from A087510.
concat(vector(6,k,B(k,3,4,isprime))) \\ Andrew Howroyd, Sep 21 2024