initial commit

55.fs

@@ -0,0 +1,23 @@
+module _55
+
+open System.Numerics
+
+let lynchrels =
+
+    let isLynchrel n =
+        let revInt (n:bigint) =
+            n
+            |> (string)
+            |> common.revString
+            |> (fun s -> BigInteger.TryParse(s) |> snd)
+
+        let rec isLynchrelRec (n:bigint,d) =
+            match (n + (revInt n)), d with
+            | _,0 -> true
+            | n,_ when ((string) >> common.isPalindrome) n -> false
+            | n,d -> isLynchrelRec (n, d-1)
+        isLynchrelRec (n,50)
+
+    [|1I..10000I|]
+    |> Array.filter isLynchrel
+    |> Array.length