OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Range[300], PrimeQ[3# (#-1)/2+1]&] (* Harvey P. Dale, Mar 09 2017 *)
PROG
(PARI) isok(n) = isprime(3*n*(n-1)/2 + 1); \\ Michel Marcus, Oct 11 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Nov 27 2006
STATUS
approved