content: --                             --- 1ERA FORMA ---
  
  esFibonacci :: Integer -> Bool
  esFibonacci n = aux17 n 0
  
  aux17 :: Integer -> Integer -> Bool
  aux17 n i | (fibonacci i) > n = False
            | fibonacci i == n = True
            | otherwise = aux17 n (i+1)  
  
  fibonacci ::Integer -> Integer 
  fibonacci n | n == 0 = 0
              | n == 1 = 1 
              | otherwise = fibonacci (n-1) + fibonacci (n-2)
  
  --                             --- 2DA FORMA ---
  
  esFibonacci2 :: Integer -> Bool
  esFibonacci2 n = auxEsFibonacci n 0 
  
  auxEsFibonacci :: Integer -> Integer -> Bool 
  auxEsFibonacci n contador | (fibonacci contador) == n = True  
                            | (fibonacci contador) /= n && ((fibonacci contador) < n) = auxEsFibonacci n (contador+1)
                            | (fibonacci contador) > n = False
  
  fibonacci :: Integer -> Integer
  fibonacci 0 = 0 
  fibonacci 1 = 1 
  fibonacci n = fibonacci (n-1) + fibonacci (n-2) 
  