Franklin Squares - a Chapter in the Scienti…c Studies of Magical Squares Peter Loly Department of Physics, The University of Manitoba, Winnipeg, Manitoba Canada R3T 2N2 (
[email protected]) July 6, 2006 Abstract Several aspects of magic(al) square studies fall within the computa- tional universe. Experimental computation has revealed patterns, some of which have lead to analytic insights, theorems or combinatorial results. Other numerical experiments have provided statistical results for some very di¢ cult problems. Schindel, Rempel and Loly have recently enumerated the 8th order Franklin squares. While classical nth order magic squares with the en- tries 1::n2 must have the magic sum for each row, column and the main diagonals, there are some interesting relatives for which these restrictions are increased or relaxed. These include serial squares of all orders with sequential …lling of rows which are always pandiagonal (having all parallel diagonals to the main ones on tiling with the same magic sum, also called broken diagonals), pandiagonal logic squares of orders 2n derived from Karnaugh maps, with an application to Chinese patterns, and Franklin squares of orders 8n which are not required to have any diagonal prop- erties, but have equal half row and column sums and 2-by-2 quartets, as well as stes of parallel magical bent diagonals. We modi…ed Walter Trump’s backtracking strategy for other magic square enumerations from GB32 to C++ to perform the Franklin count [a data…le of the 1; 105; 920 distinct squares is available], and also have a simpli…ed demonstration of counting the 880 fourth order magic squares using Mathematica [a draft Notebook].