Can anyone suggest a genuine method of solving this problem. i.e. not a method such as

    if(n==1) printf("14");
    else if(n==2) printf("155");
    else
    {
        printf("1575");
        for(i=3;i<n;i++)
        printf("0");
    }

Edited by author 24.07.2008 12:02

Edited by author 24.07.2008 12:02

I have solution ... right solution, but I have TLE #4 ... It's so slowly.

Yes,this problem has genuine algo: this is just a formula. Try to get it by yourself using this hint: write general formula for interesting numbers on paper and try to find what numbers are impossible and vise-versa. If you want see my code send me mail to bauracm@mail.ru