Let‘s consider some math problems.
JSZKC has a set A=\{1,2,...,N\}A={1,2,...,N}. He defines a subset of AA as ‘Meo set‘ if there doesn‘t exist two integers in this subset with difference one. For example, When A=\{1,2,3\}, \{1\},\{2\},\{3\},\{1,3\}A={1,2,3},{1},{2},{3},{1,3} are ‘Meo set‘.
For each ‘Meo set‘, we can calculate the product of all the integers in it. And then we square this product. At last, we can sum up all the square result of the ‘Meo set‘.
So please output the final result.
The input file contains several test cases, each of them as described below.
There are no more than 100100 test cases.
One line per case, an integer indicates the answer.
3
23
The 2018 ACM-ICPC China JiangSu Provincial Programming Contest
1 //JAVA 大数阶乘 2 import java.io.*; 3 import java.math.BigInteger; 4 import java.util.*; 5 6 public class Main 7 { 8 public static void main(String args[]) 9 { 10 Scanner cin = new Scanner(System.in); 11 int n; 12 while(cin.hasNext()){ 13 n = cin.nextInt(); //输入int型 14 BigInteger ans = BigInteger.ONE; 15 BigInteger a = BigInteger.ONE; 16 for(int i = 1; i <= n+1; i++) 17 ans = ans.multiply(BigInteger.valueOf(i)); 18 System.out.println(ans.subtract(a)); 19 } 20 } 21 }
原文：https://www.cnblogs.com/tingtin/p/9363437.html