diff --git a/lean4-mode/lean4-syntax.el b/lean4-mode/lean4-syntax.el
index 2ebdc2d4a8..b4cebca996 100644
--- a/lean4-mode/lean4-syntax.el
+++ b/lean4-mode/lean4-syntax.el
@@ -107,10 +107,10 @@
                  ?ℭ ?℮ ?ℯ ?ℰ ?ℱ ?Ⅎ ?ℳ ?ℴ ?ℵ ?ℶ ?ℷ ?ℸ ?ℹ ?℺ ?℻
                  ?ℼ ?ℽ ?ℾ ?ℿ ?⅀ ?⅁ ?⅂ ?⅃ ?⅄ ?ⅅ ?ⅆ ?ⅇ ?ⅈ ?ⅉ ?⅊
                  ?⅋ ?⅌ ?⅍ ?ⅎ ?⅏))
-    (modify-syntax-entry ?' "w" st)
-    (modify-syntax-entry ?_ "w" st)
-    (modify-syntax-entry ?! "w" st)
-    (modify-syntax-entry ?? "w" st)
+    (--map (modify-syntax-entry it "w" st)
+           (list ?₁ ?₂ ?₃ ?₄ ?₅ ?₆ ?₇ ?₈ ?₉ ?₀
+                 ?ₐ ?ₑ ?ₒ ?ₓ ?ₔ ?ₕ ?ₖ ?ₗ ?ₘ ?ₙ ?ₚ ?ₛ ?ₜ
+                 ?' ?_ ?! ??))
 
     ;; Lean operator chars
     (mapc #'(lambda (ch) (modify-syntax-entry ch "." st))