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A174240 The multiplicative order of 2 mod n, where n an odd squarefree semiprime (A046388). 2

%I

%S 4,6,10,12,12,8,20,18,12,22,30,8,28,12,10,36,36,44,24,20,14,18,46,60,

%T 28,20,52,33,58,60,36,40,66,84,20,90,70,28,15,18,24,92,78,36,82,110,

%U 36,52,22,60,48,116,132,42,100,60,102,140,106,72,36,69,132,28

%N The multiplicative order of 2 mod n, where n an odd squarefree semiprime (A046388).

%H V. Papadimitriou, <a href="/A174240/b174240.txt">Table of n, a(n) for n = 1..10000</a>.

%e For n = 1, a(1)=4 is the multiplicative order of 2 mod 15 (15 is the first odd squarefree semiprime).

%o (PARI) lista(nn) = {forstep(n=1, nn, 2, if ((bigomega(n) == 2) && (omega(n)==2), print1(znorder(Mod(2, n)), ", ")););} \\ _Michel Marcus_, Feb 05 2015

%Y Cf. A046388.

%K nonn

%O 1,1

%A _Vassilis Papadimitriou_, Mar 13 2010

%E Edited by _Ray Chandler_, Jan 09 2012

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Last modified July 22 17:02 EDT 2019. Contains 325225 sequences. (Running on oeis4.)