A Latin square of order n is a n*n square filled with n letters or numerals such that letters or numerals in each column or row are distinct. Becauce they are distinct, each letter or numeral occurs n times in the square. The following are Latin squares of order 3 and 4.
A | B | C |
B | C | A |
C | A | B |
1 | 3 | 2 | 4 |
2 | 1 | 4 | 3 |
3 | 4 | 1 | 2 |
4 | 2 | 3 | 1 |
Rule 2 of tetta, a type of shapes in cells - rectangles or triangles - are arranged as a Latin square. The letters or numerals are replaced with colors. Another type of shape are arranged as the same color in each column or row.
A Graeco-Latin square of order n is combined with two Latin squares of order n. The combinations of letters and numerals of cells in the new square are distinct. The following are four squares of order 3 and 4 each of which is combined with two Latin squares. the former two are Graeco-Latin squares, the latter not.
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Rule 3 of tetta, both types of shapes - rectangles or triangles - are arranged as a Graeco-Latin square. The letters and numerals are replaced with colors.
Order n | Total Permutations (n*n)! | Rule 1 Column-Row 2*n!*n! | Rule 2 Column/Row-Latin 4*L(n,n)*(n-1)!*n!*n! | Rule 3 Graeco-Latin |
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3 | (3*3)!=362880 | 2*3!*3!=72 | 4*1*(3-1)!*3!*3!=288 | 72 |
4 | (4*4)!=20922789888000 | 2*4!*4!=1152 | 4*4*(4-1)!*4!*4!=55296 | 6912 |
5 | (5*5)!=15511210043330985984000000 | 2*5!*5!=28800 | 4*56*(5-1)!*5!*5!=77414400 | ? |
6 | (6*6)!=3.7199332678990121746799944815084e+41 | 2*6!*6!=1036800 | 4*9408*(6-1)!*6!*6!=2341011456000 | 0(*1) |
7 | (7*7)!=6.082818640342675608722521633213e+62 | 2*7!*7!=50803200 | 4*16942080*(7-1)!*7!*7!=1239425105264640000 | ? |
8 | (8*8)!=1.2688693218588416410343338933516e+89 | 2*8!*8!=3251404800 | 4*535281401856*(8-1)!*8!*8!=17543398515000899272704000 | ? |
9 | (9*9)!=5.7971260207473679858797342315781e+120 | 2*9!*9!=263363788800 | 4*377597570964258816*(9-1)!*9!*9!=8.019287291701653098790924582912e+33 | ? |
10 | (10*10)!=9.3326215443944152681699238856267e+157 | 2*10!*10!=26336378880000 | 4*7580721483160132811489280*(10-1)!*10!*10!=1.4489707909649391634606365995965e+44 | ? |
11 | (11*11)!=8.0942985252734437396816228454494e+200 | 2*11!*11!=3186701844480000 | 4*5363937773277371298119673540771840*(11-1)!*11!*11!=1.2405611922440525795323213799888e+56 | ? |
12 | (12*12)!=5.5502938327393047895510546605504e+249 | 2*12!*12!=458885065605120000 | 4*1.62e+44*(12-1)!*12!*12!=5.93e+69(*2) | ? |
13 | (13*13)!=4.2690680090047052749392518888996e+304 | 2*13!*13!=77551576087265280000 | 4*2.51e+56*(13-1)!*13!*13!=1.86e+85(*2) | ? |
14 | (14*14)!=5.0801221108670467625027357853474e+365 | 2*14!*14!=15200108913103994880000 | 4*2.33e+70*(14-1)!*14!*14!=4.41e+102(*2) | ? |
15 | (15*15)!=1.2593608545945996091036028947807e+433 | 2*15!*15!=3420024505448398848000000 | 4*1.5e+86*(15-1)!*15!*15!=8.9e+121(*2) | ? |
16 | (16*16)!=8.5781777534284265411908227168123e+506 | 2*16!*16!=875526273394790105088000000 | ? | ? |
n! = 1*2*3*...*n
1. Graeco-Latin squares of order 6 do not exist.
2. Estimated values.
? Not zero, but unknown.
Generally speaking, numbers of rule 2 > numbers of rule 3 > numbers of rule 1
Please observe the following transformations of Latin squares of order 3. The leftmost e of them means no transformation, ie the original square; (123) means 1→2→3→1, ie changing numerals in the original square; (321) means 3→2→1→3; (12) means 1↔2; (31) means 3↔1; (23) means 2↔3. Since there are 3 numerals in a Latin square of order 3, therefore there are 3!=6 permutations in total; in other words, if the first row of the orginal Latin square is fixed at 123, and then the 3 numerals are renewed and permutated, we can get 3!=6 distinct Latin squares. Generally speaking, we can get n! distinct Latin squares through a pattern of Latin squares of order n.
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The following 2 squares are the patterns of Latin squares of order 3. The first rows are both 123; 123 means the first column is 123; 132 means the first column is 132. Each pattern represents 3!=6 distinct Latin squares, please derive them according to the above rules on your own.
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The following 24 squares are the patterns of Latin squares of order 4. The first rows of squares are all 1234; 1234 means the first columns of squares are 1234, ie the leftmost original square; 1243 means the first columns of squares are 1243, ie interchanging the 3rd and 4th rows of the leftmost original square; 1324 means the first columns of squares are 1324, ie interchanging the 2nd and 3rd rows of the leftmost original square; and so on. There are 4 squares in each column, ie although the first columns of squares are fixed, but there are 4 distinct patterns. Each pattern represents 4!=24 distinct Latin squares, please derive them according to the above rules on your own.
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Please observe the following transformations of Graeco-Latin squares of order 3. See the above paragraph for the meanings of notations. The left top is the original square. Of the 6 squares in each column, the below 5 squares are derived by permutating the letters in the topmost square; Of the 6 squares in each row, the right 5 squares are derived by permutating the numerals in the leftmost square. Since there are 3 letters and 3 numerals in a Graeco-Latin square of order 3, therefore there are 3!*3!=36 permutations in total; in other words, if the first row of the orginal Graeco-Latin square is fixed at A1 B2 C3, and then the 3 letters and 3 numerals are renewed and permutated, we can get 3!*3!=36 distinct Graeco-Latin squares. Generally speaking, we can get n!*n! distinct Graeco-Latin squares through a pattern of Graeco-Latin squares of order n.
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The following 2 squares are the patterns of Graeco-Latin squares of order 3. The first rows are both A1 B2 C3; 123 means the first column is 123; 132 means the first column is 132. Each pattern represents 3!*3!=6 distinct Graeco-Latin squares, please derive them according to the above rules on your own.
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The following 12 squares are the patterns of Graeco-Latin squares of order 4. The first rows of squares are all A1 B2 C3 D4; 1234 means the first columns of squares are 1234, ie the leftmost original square; 1243 means the first columns of squares are 1243, ie interchanging the 3rd and 4th rows of the leftmost original square; 1324 means the first columns of squares are 1324, ie interchanging the 2nd and 3rd rows of the leftmost original square; and so on. A1 B4 C2 D3 means the first columns are all composed of the 4 combinations (maybe permutated); A1 B3 C4 D2 means the first columns are all composed of the 4 combinations (maybe permutated). Each pattern represents 4!*4!=576 distinct Graeco-Latin squares, please derive them according to the above rules on your own.
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A1 B3 C4 D2 |
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