First day with week numbers
      January 0001     
   Su Mo Tu We Th Fr Sa
 1                    1
 2  2  3  4  5  6  7  8
 3  9 10 11 12 13 14 15
 4 16 17 18 19 20 21 22
 5 23 24 25 26 27 28 29
 6 30 31               
Reformation corner cases 1 with week numbers
     September 1752    
   Su Mo Tu We Th Fr Sa
36        1  2 14 15 16
37 17 18 19 20 21 22 23
38 24 25 26 27 28 29 30
                       
                       
                       
Reformation corner cases 2 with week numbers
     September 1752    
   Su Mo Tu We Th Fr Sa
36        1  2 14 15 16
37 17 18 19 20 21 22 23
38 24 25 26 27 28 29 30
                       
                       
                       
Reformation corner cases 3 with week numbers
     September 1752    
   Su Mo Tu We Th Fr Sa
36        1  2 14 15 16
37 17 18 19 20 21 22 23
38 24 25 26 27 28 29 30
                       
                       
                       
Reformation corner cases 4 with week numbers
     September 1752    
   Su Mo Tu We Th Fr Sa
36        1  2 14 15 16
37 17 18 19 20 21 22 23
38 24 25 26 27 28 29 30
                       
                       
                       
Last day with week numbers
     November 9999            December 9999            January 10000     
   Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa
45     1  2  3  4  5  6  49           1  2  3  4   1                    1
46  7  8  9 10 11 12 13  50  5  6  7  8  9 10 11   2  2  3  4  5  6  7  8
47 14 15 16 17 18 19 20  51 12 13 14 15 16 17 18   3  9 10 11 12 13 14 15
48 21 22 23 24 25 26 27  52 19 20 21 22 23 24 25   4 16 17 18 19 20 21 22
49 28 29 30              53 26 27 28 29 30 31      5 23 24 25 26 27 28 29
                                                   6 30 31