A269453 The order of 2 mod m when m is the product of two distinct safe primes.
12, 20, 30, 44, 33, 92, 110, 116, 69, 174, 164, 230, 212, 246, 290, 318, 332, 356, 410, 253, 452, 249, 530, 534, 524, 638, 678, 692, 716, 830, 393, 902, 764, 890, 932, 956, 1038, 1166, 1130, 537, 1004, 573, 1334, 1124, 1310, 1172, 1398, 717, 753, 1436, 1730, 913, 1886, 1686, 1790
Offset: 1
Keywords
Programs
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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 *)
Formula
a(n) is the order of 2 modulo A157352(n). - Wolfdieter Lang, Mar 31 2016
Extensions
More terms from Michael De Vlieger, Feb 28 2016
Comments