View Compilation Error

0_0_20826439_11612.cpp: In function 'int main()':
0_0_20826439_11612.cpp:6:5: error: '_int64' was not declared in this scope
     _int64 a[20]={0,1,2};
     ^
0_0_20826439_11612.cpp:9:9: error: 'a' was not declared in this scope
         a[i]=i*(a[i-1]+a[i-2]);
         ^
0_0_20826439_11612.cpp:11:27: error: 'a' was not declared in this scope
          printf("%I64d\n",a[n-1]);
                           ^