View Compilation Error

0_0_28129818_18923.cpp:1:1: error: stray '\246' in program
 An=Σ(0，(n+1)/2)2^(n-i)*C(n+1-i,i);
 ^
0_0_28129818_18923.cpp:1:1: error: stray '\262' in program
0_0_28129818_18923.cpp:1:1: error: stray '\243' in program
0_0_28129818_18923.cpp:1:1: error: stray '\254' in program
0_0_28129818_18923.cpp:1:1: error: 'An' does not name a type