C :

#include<stdio.h>

int main()
{
	int n,i;
	long int a,s;
	while(~scanf("%d",&n))
	{
		a=1;
		s=0;
		for(i=1;i<=n;i++) 
		{ 
           a*=i; 
           s+=a; 
		} 
	 printf("%ld\n",s);
	}
	return 0;
}

C++ :

#include<iostream>
#include<cmath>
#include<algorithm>
#include<cstring>
using namespace std;
const int N=3000;
long long jc[N]={0},ans[N]={0};
long long len1=1,len2=1;
int n;

void add()
{
	int len=max(len1,len2);
	for(int i=1;i<=len;i++)
	ans[i]+=jc[i];
	for(int i=1;i<=len;i++)
	{
		ans[i+1]+=ans[i]/10;
		ans[i]=ans[i]%10;
	}
	if(ans[len+1]!=0)
	len++;
	len2=len;
}

void mul(int i)
{
	len1=1;
	for(int j=1;j<=2999;j++)
	jc[j]=0;
	jc[1]=1;
	for(int j=1;j<=i;j++)
	{
	
	for(int l=1;l<=len1;l++)
	jc[l]=jc[l]*j;
    
	for(int l=1;l<=len1;l++)
	{jc[l+1]+=jc[l] / 10;
	jc[l]=jc[l]%10;
	}
	if(jc[len1+1]!=0)
	len1++;
	}
    add();
}

int main()
{
	cin>>n;
	for(int i=1;i<=n;i++)
	mul(i);
	for(int i=len2;i>=1;i--)
	cout<<ans[i];
	cout<<endl;
	return 0;
}

Pascal :

var
s,c:int64;
n,i,j:integer;
begin
readln(n);s:=0;
for i:=1 to n do
begin
c:=1;
for j:=1 to i do  c:=c*j;
s:=s+c;
end;
writeln(s);
end.