#include <stdio.h>

void m(int *a,int b);

void s(int *a,int b);

void d(int *a,int b);

int len = 0;

int main(){

int n1;

while(scanf("%d",&n1)==1){

if(n1<200){

printf("%d\n",(n1*n1-1)*n1*n1/12);

}else{

int num[100]={0},n2=n1,i;

for(i=0;n2>0&&i<100;i++){

num[i] = n2%10;

n2/=10;

len++;

}

m(num,n1);

s(num,1);

m(num,n1);

m(num,n1);

d(num,12);

for(i=1;i<=len;i++)printf("%d",num[len-i]);

printf("\n");

len = 0;

}

}

return 0;

}

void m(int *a,int b){

int i,temp,carry = 0;

for(i=0;i<len;i++){

temp = a[i] * b +carry;

a[i] = temp % 10;

carry = temp/10;

if(i+1==len && carry>0)len++;

}

}

void s(int *a,int b){

int i,temp,borrow = 0;

a[0] -= b;

for(i=0;i<len;i++){

a[i]-=  borrow;

if(a[i]<0){

a[i]+=10;

borrow = 1;

}if(borrow&&i==len-1)len--;

}

}

void d(int *a,int b){

int i,r=0;

for(i=len-1;i>=0;i--){

r = r * 10 + a[i];

a[i] = r/b;

r%=b;

if(r<12&&i==0)len--;

}

if(!a[len-1])len--;

}

公式不是((n²-1) * n²) / 12嗎?

檢查過了

是你的程式問題

有BUG 

減法借位忘記歸零

...謝謝^^過了