OFFSET
1,1
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..500
EXAMPLE
a(1) = 2 because 1 + 2 = 3, which is prime.
a(2) = 2 because 1 + 2 * 2 = 5, which is prime.
a(3) = 3 because 2 doesn't work, since 1 + 2 * 2 * 2 = 9 = 3^2, but 3 does work, giving 1 + 2 * 2 * 3 = 13, which is prime.
MATHEMATICA
pr = 1; Table[p = 2; While[! PrimeQ[p * pr + 1], p = NextPrime@p]; pr *= p; p, {n, 100}] (* Giovanni Resta, Jan 26 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Thomas Ordowski, Jan 26 2014
EXTENSIONS
a(11)-a(69) from Giovanni Resta, Jan 26 2014
STATUS
approved