diff --git a/extra/sequences/extras/extras.factor b/extra/sequences/extras/extras.factor
index b1196e45e0..a138525f12 100644
--- a/extra/sequences/extras/extras.factor
+++ b/extra/sequences/extras/extras.factor
@@ -524,3 +524,6 @@ PRIVATE>
 
 : change-last-unsafe ( seq quot -- )
     [ drop length 1 - ] [ change-nth-unsafe ] 2bi ; inline
+
+: replicate-into ( ... seq quot: ( ... -- ... newelt ) -- ... )
+    over [ length ] 2dip '[ _ dip _ set-nth-unsafe ] each-integer ; inline