aff.rb

# fibo O(n^2)

def fib(n)
  raise ArgumentError if n < 0

  if n == 0 || n == 1
    1
  else
    fib(n-1) + fib(n -2)
  end
end

(1..30).each do |n|
  puts "#{n} => #{fib(n)}"
end