1,3

The associated primes are in A007505.

Table of n, a(n) for n=1..43.

a(n) = A002235(n+1)-1. - R. J. Mathar, Aug 17 2009

n=0 is in the sequence because 6*2^0-1=5 is prime. n=1 is in the sequence because 6*2^1-1=11 is prime.

(PARI) is(n)=ispseudoprime(6*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Sequence in context: A194358 A018727 A161715 * A227305 A240949 A033159

Adjacent sequences: A164520 A164521 A164522 * A164524 A164525 A164526

nonn

Vincenzo Librandi, Aug 15 2009

Extended by R. J. Mathar, Aug 17 2009

a(28)-a(43) from Donovan Johnson, Jul 09 2010

approved