Issue with a particular sequence generation

[Juande Santander-Vela]

Hi all,

I'm trying to submit a sequence to the Online Encyclopedia of Integer Series (https://oeis.org/draft/A385248) and I´m generating the elements with SymPy.

This is the code I use:

```python
from sympy import Rational, log, sqrt # uses symbolic computation
phi = (1+sqrt(5))/2
def a(n): return 1 if n==0 else  int(2**n *log(phi)/log(10)-Rational(1, 2)*log(5)/log(10))+1
```

It works quite quickly and precisely even for large values of n (say 10000). However, if I try to calculate a(857) it fails.

I noticed this when trying to generate a listing of values from 0 to 1000:

```python

for i in range(0,1000+1):
    print(f"{i} {a(i)}")

```

It blocks on number 857, and so it did when doing it in reverse (with range(1000,-1,-1). It does not depend on previously calculated numbers, as calculating directly a(857) also locks.

I have raised issue 28279 with more details there... any clues of what might be happening?