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A141231 Positive integers whose prime factorizations contain only primes from A001122. 0

%I

%S 3,5,9,11,13,15,19,25,27,29,33,37,39,45,53,55,57,59,61,65,67,75,81,83,

%T 87,95,99,101,107,111,117,121,125,131,135,139,143,145,149,159,163,165,

%U 169,171,173,177,179,181,183,185,195,197,201,209,211,225,227,243,247,249

%N Positive integers whose prime factorizations contain only primes from A001122.

%t aQ[n_] := Length[Select[FactorInteger[n][[;; , 1]], # > 1 && PrimitiveRoot@# != 2 &]] == 0; Select[Range[2, 250], aQ] (* _Amiram Eldar_, Dec 09 2018 *)

%o (PARI) isokp(p) = znorder(Mod(2, p))==(p-1);

%o isok(n) = {if ((n>1) && (n % 2), my(f=factor(n)); #select(x->isokp(x), f[, 1]) == #f~; , 0); } \\ _Michel Marcus_, Dec 09 2018

%Y Cf. A001122, A000040.

%K nonn

%O 1,1

%A _Vladimir Shevelev_, Jun 16 2008

%E More terms from _Michel Marcus_, Dec 09 2018

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Last modified May 16 23:46 EDT 2021. Contains 343957 sequences. (Running on oeis4.)