Here's a strategy I use for the awesome topic "Post more bigger numbers".
For the N872yt3r sequence, take a number, X. Let's say X = 2, just so my calculator doesn't explode. (Try doing this with 8)
First, you add it to itself: 2+2=4.
Then multiply the result by itself and X: 4*2*4=32.
Then do that to the power of 2, 4, 2*4 (8) and itself (round it if you get an e+y on your calculator): 149088121440417.
Then find the factorial (Ugh) *Gulp*: Awww... my calculator exploded. Someone find the factorial of 149088121440417.
(Wolfram-Alpha can't do it!)
OK, so the N872yt3r equivalent to 2 is... 149088121440417!.