由递推式可直接推出公式,如:
f(n) = f(n-1) + n
= ( f(n-2) + n-1 ) + n
= ...
= f(1) + 2 + 3 + ... + n = 2 + 2 + 3 + ... + n = 1 + 1 + 2 + 3 + ... + n = 1 + n(n+1)/2
import java.util.Scanner;
public class Main {
public static void main(String[] args){
Scanner in = new Scanner(System.in);
int loop;
int temp;
long[] a = new long[10001];
a[1] = 2;
for(int i = 2; i < 10001; i++){
a[i] = a[i - 1] + 4 * (i - 1) + 1;
}
loop = in.nextInt();
for(int i = 0; i < loop; i++){
temp = in.nextInt();
System.out.println(a[temp]);
}
}
}