Ultramagic Squares of Order 7
Results

Partial tasks
The calculation was divided into 90 parts. In each part n(1,1) and n(2,1) were fixed.
T(1,x) is the total number of squares with n(1,1) = 1 and n(2,1) = x and n(1,2) > x
T(x,1) is the total number of squares with n(1,1) = x and n(2,1) = 1 and n(4,6) > x

Restrictions for the parameter x
The following values are not available for the parameter x:
1because the number 1 can only occur once.
25because n(4,4) = 25 is a precondition for the square to be self-complementary.
49because n(6,7) = 49 or n(7,7) = 49 as 49 is the complement value of 1.
48because in the case n(1,1) = 1 is x = n(2,1) < n(1,2) < 49
because in the case n(2,1) = 1 is x = n(1,1) < n(4,6) < 49

Table of partial results
x T(1,x) T(x,1)   x T(1,x) T(x,1)   x T(1,x) T(x,1)  
2 10971 11032   17 54163 33714   33 56225 40940  
3 14805 12388   18 54928 39271   34 54913 45353  
4 17422 15318   19 58294 35674   35 53394 40684  
5 21499 16172   20 58114 40675   36 49525 43648  
6 24188 19825   21 60299 37195   37 45498 35885  
7 28539 19968   22 59509 40657   38 43142 40704  
8 30060 23778   23 60892 36256   39 40530 34942  
9 34409 22698   24 58887 41212   40 35467 36479  
10 36486 27437   26 68566 47458   41 31393 30900  
11 40332 25558   27 69538 42359   42 27436 31202  
12 41629 30730   28 66469 47145   43 23581 25281  
13 45905 29409   29 64984 42210   44 19033 23581  
14 46978 34453   30 61937 47938   45 14082 16880  
15 49326 30872   31 63046 42199   46 9854 13013  
16 51005 37091   32 58975 46927   47 4562 7213  

Total result
a = T(1,2) + T(1,3) + ... + T(1,47) b = T(2,1) + T(3,1) + ... + T(47,1)
a = 1,920,790 b = 1,444,324
There are c = a + b so-called essentially different squares, i.e. it is not possible to derive one square from another by one of the 48 transpositions.
c = a + b = 3,365,114
2a is the total number of squares with n(1,1) = 1, including reflections at the downward main diagonal, i.e. without the condition n(2,1) < n(1,2). 2b is the total number of squares with n(2,1) = 1, including K3-transposed squares, i.e. without the condition n(1,1) < n(4,6).
2a = 3,841,580 2b = 2,888,648
There are 24 transpositions that move the number from cell (1,1) to any of the 24 axis-cells.
Thus you get 24 · 2·a = 48·a different squares with number 1 in any axis-cell.
There are 24 transpositions that move the number from cell (2,1) to any of the 24 filling-cells.
Thus you get 24 · 2·b = 48·b different squares with number 1 in any filling-cell.
Finally there are e = 48·c squares including rotated and reflected squares.
Each of these squares could be generated from one of the c essentially different squares by one of the 48 transpositions.
e = 48 · c = 161,525,472
As it is not usual to count reflected and rotated squares, the total number of different self-complementary pan-magic 7x7-squares is d = e / 8 .
d = e / 8 = 6 · c = 20,190,684
Notice that all 3,365,114 essentially different squares were saved on disk.
All other squares could be derived very easily.

Reliability
Of course I can not garantee that the results are correct. But I'm rather sure they are.
- All calculated magic squares had been tested with regard to the demanded properties.
- There are no doublets within the calculated squares.
- It could be shown that there are 3456 regular pandiagonal symmetric magic 7x7-squares. My computer-program found exactly that amount of these special squares.
- In June, 2004 Francis Gaspalou from Gif-sur-Yvette, France told me about his own computations. He got the same total number of ultramagic order-7 squares. See improvements.

Link
Prof. Grogono describes the properties of regular pan-magic squares.

Question
Can anybody confirm one of the partial results in the above table?

Index
summary cells equations transpositions improvements
results programs files conclusions samples

Walter Trump, Nürnberg, Germany, (c) 2001-04-25 (last modified: 2004-06-27)