Please help me solve a and b please

2. (24 points) The 3-fib function is similar to the Fibonacci function, except that it computes each next value as a the sum of the three previous 3-fib values (instead of the previous two). Necessarily, 3fib(1) - 3fib(2)- 3fib(3) -1. The first 7 items resulting from the function are: 1, 1, 1, 3, 5, 9, 17. (a) Write a recurrence relation to compute the 3-fib function. As we did in class, examine how each successive case of the problem is built on previous ones. Show your work. (b) Compute, using your recurrence relation, the 8th 3-fib number. Show your work