I think I figured it out for my p265 remote.
1) Press the OK + FIOS button don at the same time. The red light blinks a few times and stays on.
2) Press the CH+ button 19 times (if I counted right)
The TV will go off after the 3rd or 4th “press” . leave it off.
3) Keep clicking the CH+ until to get to about the 15th “press’. After press #16 hit the TV‒On and repeat this process until the TV comes on .
4) When it comes on it should be programed, press the “OK” button to set code.
It has been working for me.
FROM THE HORSES MOUTH !
Q: I'm trying to set up my cable/satellite/universal remote to work with your television. What is the manufacturer's code for my SEIKI TV?
A: Cable and Satellite content providers control the remote codes, and we apologize for any confusion during the remote programming. Please try the following codes:
These codes may not work on some universal remotes. If there is another code listed for SEIKI Digital in your universal remote control guide, please try that code. Refer to the Remote Control Guide under your TV's model number for more information