int main(){
	int m,i,j,k;
	scanf("%d",&m);
	int b[100000],c[100000];
	float result=0;
	b[0]=1;
	b[1]=2;
	c[0]=2;
	c[1]=3;
	for(j=0;j<m;j++){
		result=0;
	scanf("%d",&k);
	if(k>2){
	for(i=2;i<k;i++){
		b[i]=b[i-1]+b[i-2];
		c[i]=c[i-1]+c[i-2];
		result+=1.0*c[i]/b[i];
	}
	printf("%.3f\n",result+3.5);
	}
	 else if(k==2){
		result=3.5;
		printf("%.3f\n",result);
	}
	 else if(k==1){
		 result=2.0;
		 printf("%.3f\n",result);
	 }
	}
	 return 0;
}
	
