Lean-Workbook Syntax 51292: The first 1006 odd factors modulo eight

$\prod_{k=1}^{1006}(2k-1)\equiv3\pmod8$.

Source: Lean-Workbook row lean_workbook_plus_51292 (Apache-2.0), original record. This corrected declaration replaces the obsolete finite sum/product binder in with ∈ and restores required imports or namespaces. Ranges, casts, quantifiers, and mathematical expressions are preserved.