var [const] BN=Import("zklBigNum");  // libGMP
fcn fractranPrimes{
   foreach n,fr in ([1..].zip(fractranW(BN(2),fracs))){
      if(fr.num1s==1){
	 p:=(fr.toString(2) - "1").len();  // count zeros
	 if(p>1)
	    println("Prime %3d from the nth Fractran(%8d): %d".fmt(p,n,fr));
      }
   }
}
fractranPrimes();