Explanation 27x27 magic square
The 27x27 magic square is odd and 3x9. Use 3x3 an ultra magic 9x9 square to construct an ultra magic 27x27 square.
Methods to construct the 27x27 magic square are:
The first two methods lead to simple magic 27x27 squares.
The next three methods lead to simple, symmetric magic 27x27 squares.
Use the shift method to construct panmagic 27x27 squares.
The ultra magic 27x27 square is panmagic, 3x3 compact, symmetric and each 1/9 row/column gives 1/9 of the magic sum and each 1/3 diagonal gives 1/3 of the magic sum.
Construct also a 3x3 in 5x5 in 7x7 in 9x9 in 11x11 in 13x13 in 15x15 in 17x17 in 19x19 in 21x21 in 23x23 in 25x25 in 27x27 (concentric) magic square.