diff --git a/oeis2.cabal b/oeis2.cabal
--- a/oeis2.cabal
+++ b/oeis2.cabal
@@ -1,13 +1,13 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.31.2.
+-- This file has been generated from package.yaml by hpack version 0.34.1.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 4d6c16b6d6f8d31c5e4f8a743728c45f3a6f160bc1fc5600e38ab8fd6abd3863
+-- hash: 0abc3c3718c4acc9b1eb0a1cec00145536064c7795e99066f4ad9c7b637da42e
 
 name:           oeis2
-version:        1.0.3
+version:        1.0.4
 synopsis:       Interface for Online Encyclopedia of Integer Sequences (OEIS).
 description:    Release notes are here https://github.com/23prime/oeis2/releases
 category:       Math
@@ -36,7 +36,7 @@
   hs-source-dirs:
       src
   build-depends:
-      aeson >=1.1 && <1.5
+      aeson >=1.1 && <1.6
     , base >=4.7 && <5
     , containers >=0.5 && <0.7
     , http-conduit >=2.2 && <2.4
@@ -56,7 +56,7 @@
   ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       QuickCheck
-    , aeson >=1.1 && <1.5
+    , aeson >=1.1 && <1.6
     , base >=4.7 && <5
     , containers >=0.5 && <0.7
     , hspec
diff --git a/src/Math/OEIS.hs b/src/Math/OEIS.hs
--- a/src/Math/OEIS.hs
+++ b/src/Math/OEIS.hs
@@ -116,4 +116,4 @@
     _      -> sd
   where
     extend :: SeqData -> SeqData -> SeqData
-    extend sd ext = fromMaybe sd . listToMaybe . filter (sd `isPrefixOf`) $ tails ext
+    extend sd ext = fromMaybe sd . find (sd `isPrefixOf`) $ tails ext