OFFSET
1,1
COMMENTS
LINKS
Zhi-Wei Sun, Table of n, a(n) for n = 1..1000
EXAMPLE
a(1) = 5 since 3^1 + 3^1 - 1 = 5 is prime.
a(2) = 11 since 3^2 + 3^1 - 1 = 11 is prime.
MATHEMATICA
n=0; Do[If[PrimeQ[3^k+3^m-1], n=n+1; Print[n, " ", 3^k+3^m-1]], {m, 1, 310}, {k, 1, m}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Zhi-Wei Sun, Dec 23 2013
STATUS
approved