A086214 Primes of the form 3^p-2 where p is prime.

7, 241, 450283905890997361, 36472996377170786401

Offset: 1

Author

Cino Hilliard, Aug 28 2003

Keywords

• nonn

Comments

Sum of reciprocals = 0.1470065204505038552417181957...

The next two terms, 3^317-2 and 3^541-2, are too large to include. - Jorge Coveiro, Apr 05 2004

Links

• Amiram Eldar, Table of n, a(n) for n = 1..6

Crossrefs

Cf. A086218.

Programs

Mathematica

Select[3^#-2&/@Prime[Range[20]],PrimeQ] (* Harvey P. Dale, Sep 24 2022 *)

PARI

xtopm1(n,k,r) = { sr=0; forprime(p=2,n, y=k^p-r; if(isprime(y),print1(y","); sr+=1./y; ); ); print(); print(sr) }