maple_calculations.mw

Why does my sequence return 0 at n=9 and n=10, when it should be 4?

Beneath the sequence i have also calculated the limit of f, as x approaches infinity, and it returns 4.

Below the initial screenshot, i have displayed a screenshot of the same plot but with a much bigger x-axis. It seems something weird happens at very large numbers of x. Is it a glitch, and if so how do i fix it?

here is the maple document containing the calculations below: maple_calculations.mw