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Least prime p such that p+6^k is prime for all k=0,...,n.
1

%I #28 Jul 05 2017 02:56:56

%S 2,5,5,7,7,131,1087,1087,1087,3599111

%N Least prime p such that p+6^k is prime for all k=0,...,n.

%C The function f(k;p) = p+6^k could be termed an example of a non-polynomial prime generating function.

%C Since 6^n (mod 11) cycles through 6,3,7,9,10,5,8,4,2,1,... there is no a(10). - _John Cerkan_, Jul 01 2017

%H C. Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_782.htm">Puzzle 782. Prime-Generating non-polynomials</a>, primepuzzles.net, April 4, 2015.

%o (PARI) a(n)=forprime(p=1,,for(i=1,n,ispseudoprime(p+6^i)||next(2));return(p))

%K nonn,fini,full

%O 0,1

%A _M. F. Hasler_, Apr 05 2015

%E Keywords fini,full added by _John Cerkan_, Jul 01 2017