Remember that Fibonacci's sequence is a sequence of numbers where every number is the sum of the previous two numbers. For this problem, implement Fibonacci recursively, with a twist! Imagine that we want to create a new number sequence called Fibonacci-3. In Fibonacci-3, each number in the sequence is the sum of the previous three numbers. The sequence will start with three 1s, so the fourth Fibonacci-3 number would be 3 (1+1+1), the fifth would be 5 (1+1+3), the sixth would be 9 (1+3+5), the seventh would be 17 (3+5+9), etc.
Name your function fib3, and make sure to use recursion.
The lines below will test your code.
If your function is correct, they will print 1, 3, 17, and 57.
print(fib3(3))
print(fib3(4))
print(fib3(7))
print(fib3(9))