Formal target: Corpus.OEIS308734.conjecture
**Zhi-Wei Sun's Four-Square Conjecture (A308734)**: Any integer $n > 1$ can be written as $(2^a \cdot 3^b)^2 + (2^c \cdot 5^d)^2 + x^2 + y^2$ for nonnegative integers $a, b, c, d, x, y$.
Exact formal statement
∀ (n : Nat), LT.lt.{0} 1 n → Corpus.OEIS308734.A nThis target is a formal statement, not a proof of the problem.
Environment availability: available.