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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
OFFSET
1,1
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 A373460
KEYWORD
nonn
AUTHOR
Cino Hilliard, Jun 29 2005
STATUS
approved