This projects includes three different methods for generating Fibonacci numbers at a given index. Recursion, Recursion with memoization and Binet’s Fibonacci number formula in both Swift and Objective-C. It's been updated to Swift 3 syntax.
Medium Post: Fibonacci Sequence
The Swift examples are in Xcode Playgrounds. All you need is Xcode 8.x to run.
The Objective-C examples were written with CodeRunner 2, you may be able to run them a different way, but I haven't tried.
These examples are made available under the MIT license. See the LICENSE file for more info.