A256300 Least prime p such that p+6^k is prime for all k=0,...,n.

2, 5, 5, 7, 7, 131, 1087, 1087, 1087, 3599111

Offset: 0

Author

M. F. Hasler, Apr 05 2015

Keywords

• nonn
• fini
• full

Comments

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

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

Links

• C. Rivera, Puzzle 782. Prime-Generating non-polynomials, primepuzzles.net, April 4, 2015.

Programs

PARI

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

Extensions

Keywords fini,full added by John Cerkan, Jul 01 2017