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A108258 Consider primes p and q such that p = 3^k + 20 and q = 3^(k+1) + 20 for some k; sequence gives values of q. 1
29, 47, 101, 263, 6581, 177167 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

3^1 + 20 = 23, 3^2 + 20 = 29.

MATHEMATICA

Transpose[Select[Partition[#+20&/@(3^Range[50]), 2, 1], AllTrue[ #, PrimeQ]&]] [[2]] (* The program uses the function AllTrue from Mathematica version 10 *) (* Harvey P. Dale, Oct 29 2014 *)

PROG

(PARI) g(m, n, b) = { for(x=0, n, y=m+b^x+b%2; z=m+b^(x+1)+b%2; if(isprime(y)&isprime(z), print1(z", ") ) ) }

CROSSREFS

Cf. A108249.

Sequence in context: A106754 A222413 A063642 * A232236 A228585 A042947

Adjacent sequences:  A108255 A108256 A108257 * A108259 A108260 A108261

KEYWORD

nonn

AUTHOR

Cino Hilliard, Jun 29 2005

STATUS

approved

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Last modified May 22 21:50 EDT 2019. Contains 323504 sequences. (Running on oeis4.)