OFFSET
1,2
COMMENTS
a(17) > 2*10^5. - Robert Price, Mar 20 2015
REFERENCES
R. K. Guy, Unsolved Problems in Theory of Numbers, Section A3.
LINKS
Steven Harvey, Williams Primes
H. C. Williams, The primality of certain integers of the form 2Ar^n - 1, Acta Arith. 39 (1981), 7-17.
MATHEMATICA
Do[ If[ PrimeQ[11*12^n - 1], Print[n]], {n, 1, 2000}]
Select[Range[10000], PrimeQ[(11 12^# - 1)] &] (* Vincenzo Librandi, Mar 21 2015 *)
PROG
(PARI) for(n=1, 2000, if(isprime(11*12^n-1), print1(n, ", ")))
(Magma) [n: n in [1..600]| IsPrime(11*12^n - 1)]; // Vincenzo Librandi, Mar 21 2015
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Robert G. Wilson v, Jan 16 2003
EXTENSIONS
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008
a(13)-a(16) from Robert Price, Mar 20 2015
STATUS
approved