OFFSET
1,1
COMMENTS
An odd prime p is in the sequence iff p is not in A028491.
PROG
(PARI) isokd(n) = (n!=1) && !isprime(n) && (gcd(n, 3)==1) && (znorder(Mod(3, n)) * (sumdiv(n, d, eulerphi(d)/znorder(Mod(3, d))) - 1) + 1 == n); \\ A141350
isok(n) = {fordiv (3^n-1, d, if (isokd(d), return (1)); ); return (0); }
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Jun 30 2008
EXTENSIONS
More terms from Michel Marcus, Oct 25 2018
STATUS
approved