theorem proved term proof

`mobius_twentyone`

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formal statement (Lean)

1107theorem mobius_twentyone : mobius 21 = 1 := by native_decide

Term-mode proof.

1108
1109/-- μ(35) = 1 (squarefree with 2 prime factors). -/

Lean names referenced from this declaration's body.

mobius in IndisputableMonolith.NumberTheory.Primes.ArithmeticFunctions decl_use