A243279 Numbers n such that (46^n - 1)/45 is prime.

2, 7, 19, 67, 211, 433, 2437, 2719, 19531

Offset: 1

Author

Robert Price, Jun 02 2014

Keywords

• hard
• more
• nonn

Comments

a(10) > 10^5.

Numbers corresponding to a(7)-a(9) are probable primes.

All terms are prime.

Links

• Harvey Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
• Henri Lifchitz, Mersenne and Fermat primes field

Crossrefs

Cf. A028491, A004061, A004062, A004063, A004023, A005808, A004064, A016054, A006032, A006033, A006034, A006035, A127995, A127996, A127997, A127998, A127999, A098438, A128002, A128003, A128004, A128005, A240765, A242797.

Programs

Maple

A243279:=n->`if`(isprime((46^n - 1)/45), n, NULL); seq(A243279(n), n=1..100000); # Wesley Ivan Hurt, Apr 12 2014

Mathematica

Select[Prime[Range[100000]], PrimeQ[(46^# - 1)/45] &]

PARI

is(n)=ispseudoprime((46^n-1)/45) \\ Charles R Greathouse IV, May 22 2017