In 2002 Walter Trump investigated unusual
magic squares which he decided to call ultramagic. Most of the wording,
and all of the examples shown here is from material condensed from several emails and
attached spreadsheets sent to me in February 2002.
Some of this work was in collaboration with George Chen.
Square a. is one of 17 order7 Walter found that are all pandiagonal, center symmetrical (=associative), and contain two magic 3x3 arrays
These are squares 04347674 and 06969925 from Trump's database of 20,190,684 squares.
Squares b., c., and d. are 1 of 11 magic squares of order 7 with following features
There are 96 magic squares of order 7 with the following features
Mathematical statement (easy to proof):
If a magic square fulfils the conditions 1 and 3, then it also owns the features 5
If a magic square fulfils the conditions 1 and 4, then it also owns the features 6
If a square is center symmetric, then two rows or two columns symmetrically located to the center have equal squaressums and equal thirdpowerssums
The complete set (96 squares) consist of 16 sets, each containing 6 squares that belong to the same transformationgroup. From each of the 16 groups I show only one square.
There are 11 magic squares of order 7 with the following features

There are 20 magic squares of order 7 with the following features
pandiagonal
center symmetric (associative)
letter H as quadrant magic pattern
a magic 3 by 3 array is inlaid (red numbers)
Additional features of square 14
the sum of the squares of all numbers in the middle row is the same as in the middle column
the sum of the cubes of all numbers in the middle row is the same as in the middle column
There are 30 magic squares of order 7 with following the features
The numbers in each tile sum up to 3x25 = 75 Square 00384300 
These 4 types of ultra letter squares are all pandiagonal center symmetric (associated) magic a. the sum of the 10 numbers in each letter A sum to 250. The squares of these numbers sum to 8362. There are 11 order7 magic squares with these features. b. the sum of the 7 numbers in each letter C and H sum to 175. The squares of these numbers sum to 5721. There is only 1 magic square with these features? Squares c. and d. are shown twice because the patterns overlap. c. the sum of the 10 numbers in each letter A sum to 250. The squares of these numbers sum to 7622. There are 5 magic squares with these features. d. the sum of the 10 numbers in each letter A and W sum to 250. There are 60 magic squares with these features. 
Walter Trump has a web page on this subject with much more detailed information at http://www.nefkom.net/trump/magicsquares
.Please send me Feedback about my Web site!
Harvey Heinz harveyheinz@shaw.ca
First posted July 2008
Last updated October 05, 2009
Copyright © 2008 by Harvey D. Heinz