A190942 Numbers n such that 2*71^n + 1 is prime.

0, 3, 29, 83, 153, 327, 753, 879, 3333, 36977

Offset

1,2

Comments

a(11) > 10^5. - Robert Price, Jan 12 2016

Links

Table of n, a(n) for n=1..10.

Chris K. Caldwell, The List of Largest Known Primes, 2 * 71^879 + 1

Chris K. Caldwell, The List of Largest Known Primes, 2 * 71^3333 + 1

Chris K. Caldwell, The List of Largest Known Primes, 2 * 71^36977 + 1

Mathematica

Select[Range[0, 10^3], PrimeQ[2*71^# + 1] &] (* Arkadiusz Wesolowski, Jul 29 2011 *)

Prog

(Magma) [n : n in [0..10^3] | IsPrime(2*71^n+1)]; // Arkadiusz Wesolowski, Jul 29 2011
(PARI) for(n=0, 10^3, if(isprime(2*71^n+1), print1(n, ", "))) \\ Arkadiusz Wesolowski, Jul 29 2011

Crossrefs

Cf. A141774, A141798.

Sequence in context: A221745 A087210 A288918 * A106943 A281712 A106942

Adjacent sequences: A190939 A190940 A190941 * A190943 A190944 A190945

Keyword

nonn,hard,more

Author

Arkadiusz Wesolowski, May 24 2011

Status

approved