OFFSET
1,1
COMMENTS
The smallest positive integer k for which 2^k == 1 (mod m) where m = p*q with p, q distinct safe primes.
FORMULA
a(n) is the order of 2 modulo A157352(n). - Wolfdieter Lang, Mar 31 2016
MATHEMATICA
MultiplicativeOrder[2, #] & /@ Select[Select[Range@ 4200, PrimeNu@ # == 2 &], Times @@ Map[If[PrimeQ[(# - 1)/2], #, 0] &, Map[First, FactorInteger@ #]] == # &] (* Michael De Vlieger, Feb 28 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Marina Ibrishimova, Feb 27 2016
EXTENSIONS
More terms from Michael De Vlieger, Feb 28 2016
STATUS
approved