Function is_decomposable_sq 

pub fn is_decomposable_sq(n: usize) -> bool

Is Sqⁿ decomposable — a Z/2 combination of products SqᵃSqᵇ (a, b ≥ 1) — in the Steenrod algebra? Decided by reducing every such product to the admissible basis (Adem) and testing whether Sqⁿ lies in their span.