Moved 1 to 5 to Python and learned a ton.

python/lib_fibonacci.py

@@ -0,0 +1,44 @@
+def fibonacci_generator():
+    """
+    Fibonacci generator function that starts with 1, 1, 2, 3, ...
+
+    :returns: generator that yields fibonacci numbers
+    """
+    a = 0
+    b = 1
+    yield b
+    while True:
+        a, b = b, (a + b)
+        yield b
+
+
+def fibonacci_generator_smaller(n):
+    """
+
+    :param n: generator yields all fibonacci numbers smaller n
+    :returns: generator that yields fibonacci numbers
+
+    """
+    g = fibonacci_generator()
+    x = next(g)
+    while x < n:
+        yield x
+        x = next(g)
+
+
+def fibonacci_nth(n):
+    """
+
+    :param n: index of fibonacci that should be returned
+    :returns: nth fibonacci number
+
+    """
+    if n < 1:
+        return 0
+    g = fibonacci_generator()
+    i = 1
+    x = next(g)
+    while i < n:
+        i += 1
+        x = next(g)
+    return x