This specific code just refuses to compile?
As Majenko stated in the comments, your use of the println function is not valid as there exists no overload that takes char*, int, int as parameters.

You could get your program to work by replacing your println as following:

for(int i = 0; i &lt; 51; i++){
    Serial.print(notes[i]);
    Serial.print("'s sharp is ");
    Serial.println(notes[i]+(notes[i]*0.05937));
}