OFFSET
1,1
COMMENTS
The corresponding primes are 2, 5, 2, 13, 41, 73.
EXAMPLE
4 is in the sequence since lambda(4) = 2 and (3^2 - 1)/4 = 2 is prime.
MATHEMATICA
aQ[n_] := PrimeQ[(3^CarmichaelLambda[n]-1)/n]; a={}; Do[If[aQ[k], AppendTo[a, k]], {k, 1, 10000}]; a
PROG
(PARI) isok(n) = (denominator(p=(3^lcm(znstar(n)[2])-1)/n)==1) && isprime(p); \\ Michel Marcus, Dec 29 2017
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Amiram Eldar, Dec 29 2017
STATUS
approved