Update duckdb index files

.gitattributes

@@ -56,3 +56,4 @@ saved_model/**/* filter=lfs diff=lfs merge=lfs -text
 stackmathqa100k/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 stackmathqa1600k/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 stackmathqa200k/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+stackmathqa400k/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

stackmathqa400k/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e3d6d76322014da47f89c8c1a0244f40b028c7972710a34e04c38cacfb8325f4
+size 842018816