The code for the remote control on your Sylvania television will be contained in the instruction manual and is unique to your television and remote control. This is done to provide you with an additional security aspect and means that the television is harder to use without the code for the remote.
When you get your television it's vital that you follow the instructions to the word. This will include the security codes and devices for both the television and remote control. As well as providing you with security the code on the remote can prevent anyone else from viewing pay-per-view programming onto your account. Keeping the manual with the security code in a safe place simply follows natural security measures, you should do the same with any electronic device and also keep back-up copies of the codes and passwords in a secure place.
A television without a remote control is almost worthless - another user may be able to watch the television but without the features provided by the remote control the television is working at less than 50% of it's capacity. Being unable to switch channels, pause the television or record programs makes the re-sale value of a television almost worthless which is the major deterrent to a thief.
These sort of devices are standard now in modern televisions, a television without these security features is less attractive since it will be easier to sell on in the event of theft. By looking after your security features, storing them safely and having back up copies you are making life easier for yourself and avoiding the disruption of having to go back to the makers and the drawn out process of resetting the security features.