Series Program 3

(1) + (1+2) + (1+2+3) + (1+2+3+4) + ... + (1+2+3+4+...+n)

int main()
{
    int i,j,n,sum=0;
    n=10;
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=i;j++)
        {
            sum+=j;
        }
    }
    printf("Sum: %d",sum);
    return 0;
}