Q1. THE FIRST ATTENDANCE QUESTION WAS:
Finish the proof

A1. MY ANSWER TO THE FIRST ATTENDANCE QUESTION IS:
Suppose the proposition is true up to k,
then for graph of k+1 vertices, we know it contains graph of k vertices and k-1 edges with no cycles.
Adding a vertex and an edge to it would not make a cycle since the new vertex is a leaf. 


Q2. THE  SECOND ATTENDANCE QUESTION WAS:
What is the a number of 1, 1, 3, 16, 125, 1296, 16807, 262144, 4782969, 100000000

A2. MY ANSWER TO THE  SECOND ATTENDANCE QUESTION IS:
A000272


Q3. THE  THIRD ATTENDANCE QUESTION WAS:
What is the a number of 0, 0, 1, 15, 222, 3660, 68295, 1436568, 33779340, 880107840

A3. MY ANSWER TO THE  THIRD ATTENDANCE QUESTION IS:
A057500


Q4. THE  FOURTH ATTENDANCE QUESTION WAS:
What is time(TreeSeq(75))/time(TreeSeq1(75))

A4. MY ANSWER TO THE  FOURTH ATTENDANCE QUESTION IS:
73.12480000


Q5. THE  FIFTH ATTENDANCE QUESTION WAS:
Set up a functional equation of number of rooted trees where every vertex has an even number of children

A5. MY ANSWER TO THE  FIFTH ATTENDANCE QUESTION IS:



Q6. THE  SIXTH ATTENDANCE QUESTION WAS
How many labelled ttrees are there with 27 vertices and 6 leaves

A6. MY ANSWER TO THE  SIXTH ATTENDANCE QUESTION IS
7776


Q7. THE  SEVENTH ATTENDANCE QUESTION WAS


A7. MY ANSWER TO THE  SEVENTH ATTENDANCE QUESTION IS



Q8. THE  EIGHTH ATTENDANCE QUESTION WAS


A8. MY ANSWER TO THE  EIGHTH ATTENDANCE QUESTION IS