JAVA | 100分求1的1次方+2的2次方+3的3次方+4的4次方+。。。+20的20次方的算法

public class Main {
public static void main (String []args) {
double t=0;
int i;
int j=1;
for(i=1;i<=20;i++){
j=1;
for(int k=1;k<=i;k++){
j=j*i;
}
t+=j;
}
System.out.println(t);
}
}
3.766126E9
给分来

public class Jc {
public static void main (String []args) {
System.out.println (jc(5));
}
public static int jc (int i) {
int j=1;
int s=1;
int k=0;
while (j<=i){
s=s*j;
k=s+k;
j++;
}
return k;
}
}

求出每个加数的乘方再相加之和，详细算法略

Hello guy!
The following code is achieved as enterprise business app,Maybe you
are searching for which is explicitly used numeric analysis...
Just hope a little help for you! Thank you...

import java.math.BigDecimal;

public class BigDecimalTest {

public static BigDecimal function(int index) {
BigDecimal num = new