diff --git a/Basis/NucInt.ml b/Basis/NucInt.ml
index e551c8d..dd6d416 100644
--- a/Basis/NucInt.ml
+++ b/Basis/NucInt.ml
@@ -19,7 +19,7 @@ let zero_m ~maxm ~expo_pq_inv ~norm_pq_sq =
   let t = norm_pq_sq *. exp_pq in
   boys_function ~maxm t
   |> Array.mapi (fun m fm ->
-      two_over_sq_pi *. (if m mod 2 = 0 then fm else -.fm) *.
+      two_over_sq_pi *. fm *.
       (pow exp_pq m) *. (sqrt exp_pq)
     )