OFFSET
1,1
COMMENTS
Some of the larger entries may only correspond to probable primes.
The values corresponding to 1193 (719 digits) and 1993 (1200 digits) have been certified prime with Primo. - Rick L. Shepherd, Sep 10 2002
8 more terms found by Jean-Louis Charton during 2004 - 2006. Corresponding numbers of decimal digits are 14461, 27876, 28972, 41300, 54958, 79170, 89505, 111058, 205443. - Alexander Adamchuk, Dec 02 2006
LINKS
Bogley, William A.; Williams, Gerald Efficient finite groups arising in the study of relative asphericity. Math. Z. 284, No. 1-2, 507-535 (2016).
MATHEMATICA
Select[Range[1000], PrimeQ[4^# - 3^#] &] (* Alonso del Arte, Nov 03 2011 *)
PROG
(PARI) select(vector(10^5, i, i), n->ispseudoprime(4^n-3^n)) \\ Charles R Greathouse IV, Feb 11 2011
CROSSREFS
KEYWORD
nonn,nice,hard
AUTHOR
Mike Oakes, Feb 23 2001
STATUS
approved