A087538 Primes consisting only of digits 8 and 9 occurring with equal frequency.

89, 88989899, 98988899, 98989889, 99898889, 8889899899, 8889988999, 8889998899, 8898988999, 8898989989, 8899889989, 8988998899, 8988999889, 8989889899, 8989889989, 8989899889, 8989988899, 8998998889, 8999888899, 9888899899, 9888989899, 9889898899, 9889988989

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

• Andrew Howroyd, Table of n, a(n) for n = 1..5275

Crossrefs

Cf. A087510, A087511, A087537.

Programs

PARI

\\ Needs B() from A087510.
concat(vector(6,k,B(k,8,9,isprime))) \\ Andrew Howroyd, Sep 20 2024

Extensions

Edited by Charles R Greathouse IV, Oct 28 2009

Offset changed and a(20) onwards from Andrew Howroyd, Sep 20 2024