Fibonacci n-step number sequences: Difference between revisions

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@@ Line 3,480: / Line 3,480: @@
 # A000032 :: () -> [Int]
 def A000032():
-    '''Non finite sequence of Lucas numbers
+    '''Non finite sequence of Lucas numbers.
     '''
+    return unfoldr(recurrence(2))([2, 1])
-    def relation(xs):
-        return xs[0], xs[1:] + [sum(take(2)(xs))]
-    return unfoldr(relation)([2, 1])
@@ Line 3,493: / Line 3,490: @@
        defined by a recurrence relation.
     '''
+    return unfoldr(recurrence(n))(
-    def relation(xs):
-        return xs[0], xs[1:] + [sum(take(n)(xs))]
-    return unfoldr(relation)(
         take(n)(
             chain(
@@ Line 3,504: / Line 3,498: @@
         )
     )
+# recurrence :: Int -> [Int] -> Int
+def recurrence(n):
+    '''Recurrence relation in Fibonacci and related series.
+    '''
+    def go(xs):
+        return xs[0], xs[1:] + [sum(take(n)(xs))]
+    return go