diff --git a/journal/2023-09-29.md b/journal/2023-09-29.md
index c0cd9c647..88d5cfd3c 100644
--- a/journal/2023-09-29.md
+++ b/journal/2023-09-29.md
@@ -14,4 +14,4 @@
         - 190 + 19 is 209 precisely, so it is a multiple.
       - Therefore 209 is 11 * 19.
   - [[1547]] is not prime; it is 7 * 13 * 17.
-    - I don't remember how I got here but it was fun.
+    - I got to this one by whistling a 1547 tone, then checking https://anagora.org/prime/1547 :)