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theorem proved term proof

balanced_prime_twohundredfiftyseven

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formal statement (Lean)

2117theorem balanced_prime_twohundredfiftyseven : Prime 257 ∧ Prime 251 ∧ Prime 263 ∧ (251 + 263) / 2 = 257 := by native_decide

proof body

Term-mode proof.

2118
2119/-! ### Practical numbers (every m ≤ n is a sum of distinct divisors of n) -/
2120
2121/-- σ_1(1) = 1 ≥ 1, so 1 is practical. -/

depends on (10)

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