Sn(x) = The Smallest Positive Integer Bigger than the Biggest Positive Integer defined in Sn(x-1)+1 symbols using only Well-Defined Functions where Sn(0) = 0
A symbol here refers to any Mathematical Symbols, (e.g. Numbers, Notations, Functions,...). Thus:
Sn(0) = 0
Sn(1) = 9
Sn(2) = Pi(f⁹⁹(9↑↑↑↑9)) where f is LNGN Function,(Maybe).
Sn(3) = Impossible to find.
Sn's Number = Sn(10⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴⁴).
All we know is that it uses Well-Defined Functions, so i use the Largest current Well-Defined Function combined with another Function Explained Below, Sn(2) is already Larger than LNGN. If Sn's Number is Well-Defined then it is way bigger than Large Number Garden Number. But since the LNGN Function is the Largest Well-Defined Function, Sn's Number would be an Extension of LNGN, to avoid this, we use a new Well-Defined Function:
Pi(n) = The Largest Well-Defined Expression that can be Expressed using n Mathematical Symbols.
Symbols here are not Functions, but any kind of thing can generate a Big and Well-Defined Expression, (e.g. like 9*9^3/1). With this Function we avoid the Number being an Extension of LNGN, since we use it at the start of any Expression Named in Functions, and LNGN Function is currently the Largest Well-Defined Function, of course, it will probably be a Salad Number. But since i will not define a Number with Pi(n),Sn's Number isn't a Naive Extension of any Number.