Add solution for problem 65.

Problem065.hs

@@ -0,0 +1,10 @@
+-- Find the sum of digits in the numerator of the 100th convergent of the continued fraction for e.
+import Euler
+
+convergent n = go $ take n e_cf
+  where
+    go [a]    = a
+    go (a:as) = a + recip (go as)
+    e_cf      = 2 : concatMap (\k -> [1, 2*k, 1]) [1..]
+
+main = print $ sum $ (\x->x::[Integer]) $ toDigits $ numerator $ convergent 100