A318759 - OEIS

%I #23 Oct 12 2018 21:07:17

%S 1,2,3,4,6,9,12,13,18,20,27,29,36,39,40,54,60,65,81,87,108,109,117,

%T 120,121,136,146,162,180,182,195,197,243,245,261,263,272,324,327,328,

%U 332,351,360,363

%N Numbers x whose trajectory reaches 1 under recursive applications of the map x -> x/3 if x == 0 (mod 3), x -> (4*x+2)/3 if x == 1 (mod 3), x -> (4*x+1)/3 if x == 2 (mod 3).

%o (C++)

%o #include <iostream>

%o using namespace std;

%o void Number_Generator();

%o int main()

%o {

%o     Number_Generator();

%o     return 0;

%o }

%o void Number_Generator()

%o {

%o     int Number_Tested=1; int Temporary;

%o     int Divideby=3;

%o     //For numbers bigger than this you need to use unsigned long int or do some large number implementation.

%o     int Limit=38000;

%o     while(Number_Tested<Limit)

%o     {

%o         Temporary=Number_Tested;

%o         //There are two cycles. 1 and 7 are the smallest numbers in those cycles.

%o         while((Temporary!=1) && (Temporary!=7))

%o         {

%o             if(Temporary%Divideby)

%o                 Temporary=(Temporary*(Divideby+1)+(Divideby-(Temporary%Divideby)))/Divideby;

%o             else

%o                 Temporary=Temporary/Divideby;

%o         }

%o         if(Temporary==1)

%o             cout<<Number_Tested<<"\n";

%o         Number_Tested++;

%o     }

%o }

%Y Cf. A014682, A126241, A138754.

%K nonn

%O 1,2

%A _Jack Warren_, Sep 02 2018