Formal target: Corpus.OEIS224.conjecture
$n^2 \equiv 1 \pmod{a(n)(a(n)-1)}$ if and only if $n$ is an odd prime.
Exact formal statement
∀ (n : Nat),
LT.lt.{0} 1 n →
Iff (And (Nat.Prime n) (Ne.{1} n 2))
((HMul.hMul.{0, 0, 0} (Corpus.OEIS224.a n) (HSub.hSub.{0, 0, 0} (Corpus.OEIS224.a n) 1)).ModEq
(HPow.hPow.{0, 0, 0} n 2) 1)This target is a formal statement, not a proof of the problem.
Environment availability: available.