#ATTENDANCE QUIZ FOR LECTURE 18 of Dr. Z.'s Math454(02) Rutgers University


# Please Edit this .txt page with Answers


#Email  ShaloshBEkhad@gmail.com 
#Subject: p18
#with an attachment called
#p18FirstLast.txt
#(e.g. p18DoronZeilberger.txt)


#Right after finishing watching the lecture but no later than Nov. 10, 2020, 8:00pm




THE NUMBER OF ATTENDANCE QUESTIONS WERE: 8


PLEASE LIST ALL THE QUESTIONS FOLLOWED, AFTER EACH, BY THE ANSWER


1. Who invented Latin Squares and Latin-Greco squares? What are they? 
A: 
 Choi Seok-jeong published one of the first Latin Squares, but it was invented by Euler. Latin Squares n × n array filled with n different symbols, each occurring exactly once in each row and exactly once in each column. Latin-Greco Squares are arranged so that every row and every column contains each element of S and each element of T exactly once, and that no two cells contain the same ordered pair. Latin-Greco Squares are n x n squares consisting of elements s from set S and t from set T. 


2. What is nops(AllGraphs(20))? 
A: very large number 


3. What is CC(G,38)? 
A: {{1}}


4. Is this sequence in the OEIS? 
A: Yes - A001187


5. Draw this graph manually 8-1-4-6-9
A:  
8-1-4-6-9
 |  |  |  |
7  2 3 5


6. (i) Is this sequence in the OEIS? 
(ii) What is the A number? 
(iii) What is the number of labeled trees with 20 vertices? 


A: 
(i) Yes
(ii) A000272
(iii) 5480386857784802185939 


7. Is this in the OEIS? 
A: Yes (A057500) because it is the number of unicyclic graphs on n labeled nodes 


8. Is this in the OEIS? 
A: yes - A061540