shift click the green flag to start turbo mode, it'll make the simulation run faster. space hides the list, which can let the program run much, much faster. p pauses, but it's laggy press the left arrow on your keyboard to enter "slow advance" mode. then press the right arrow to advance one number. this is helpful if you want to see, for example, what the 13,687th prime is without scrolling around.
for a faster version of this same program (unfortunately no list of numbers on this one), visit https://phosphorus.github.io/#196715762