OFFSET
1,1
COMMENTS
No other terms < 100000. - Robert Price, Dec 23 2011
LINKS
H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
H. Lifchitz, Mersenne and Fermat primes field
Index to primes in various ranges, form ((k+1)^n-1)/k
MATHEMATICA
Select[Prime[Range[100]], PrimeQ[(38^#-1)/37]&]
PROG
(PARI) is(n)=ispseudoprime((38^n-1)/37) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Alexander Adamchuk, Feb 11 2007
EXTENSIONS
a(5) corresponds to a probable prime discovered by Paul Bourdelais, Oct 17 2017
STATUS
approved