added fibonacci sequence

Author: Cortys

algorithms/math/fibonacci.clj

@@ -0,0 +1,10 @@
+(ns math.fibonacci)
+
+(defn fibonacci [n]
+  (cond
+    (<= n 0) 0
+    (<= n 2) 1
+    :else
+    (loop [i 2, a 1N, b 1N]
+      (if (= i n) b
+        (recur (inc i) b (+ a b))))))