OFFSET
1,2
COMMENTS
This sequence is closed under multiplication, i.e., if x and y are terms then so is x*y.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
v={}; Do[If[IntegerQ[(3^n^2-1)/n], v=Append[v, n]; Print[v]], {n, 2500}]
Select[Range[1400], Divisible[3^#^2-1, #]&] (* Harvey P. Dale, Nov 04 2015 *)
PROG
(PARI) isok(k) = Mod(3, k)^(k^2) == 1; \\ Amiram Eldar, May 26 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Farideh Firoozbakht, Mar 31 2004
STATUS
approved