How do I code this equation in python (factor ceiling(2^127-1))

[Pleiades]

how do you write ceiling(2^127-1)-1? i can understand (2^127-1)-1 but i don't understand ceiling() in the context of factoring. ceiling(170141183460469231731687303715884105727)-1?

---

are you trying to compile a list of Mersenne Primes?

Skaperen I'm trying to predict Mersenne Primes and I know that is nuts, but I have spare time so what the heck lol.

---

cypari gives some result:

 >>> import cypari >>> cypari.pari('factor({})'.format(2**127-2)) [2, 1; 3, 3; 7, 2; 19, 1; 43, 1; 73, 1; 127, 1; 337, 1; 5419, 1; 92737, 1; 649657, 1; 77158673929, 1] 

Hi,
I'm now trying to do this calculation at the interpreter and I get this error. Maybe in 10 years I'll see the answer to this one. No bad on you, but this is very complex.
My computer is running the latest version of mpmath 1.0.0

ERROR_
3**1279 % 19.1
OverflowError: int too large to convert to float