4prime:=function(k,n)
	local i,j,s;
	for i in [k..n] do 
		s:=0;
		for j in [2*i..3*i] do 
			if IsPrime(j) then
				s:=s+1;
			fi;
		od;
		if s<4 then
			Print(i);
			return  false;
		fi;
	od; return true;
end;