Smallest possible pandiagonal Sudoku

In her interesting article "Constructing pandiagonal magic squares of arbitrarily large size" (Mathematics Today, February 2006), Kathleen Ollerenshaw on page 25 writes:

"It is probable that no Sudoku solution can be Latin pandiagonal magic, but I have made no attempt to prove this".

Her surmise is correct, no 9x9 Sudoku solution can be pandiagonal. In the April 2006 issue, my letter on this subject is published after the second part of Ollerenshaw's article.

This 25x25 Sudoku, published in Mathematics Today,
is a pandiagonal Latin square. Each sub-square, row, column, diagonal, broken diagonal contain all numbers from 1 to 25. It is impossible to construct a pandiagonal Latin square of a smaller composite order (including the impossibility of a 9x9 pandiagonal Sudoku)

2	25	18	11	9	3	21	19	12	10	4	22	20	13	6	5	23	16	14	7	1	24	17	15	8
14	7	5	23	16	15	8	1	24	17	11	9	2	25	18	12	10	3	21	19	13	6	4	22	20
21	19	12	10	3	22	20	13	6	4	23	16	14	7	5	24	17	15	8	1	25	18	11	9	2
8	1	24	17	15	9	2	25	18	11	10	3	21	19	12	6	4	22	20	13	7	5	23	16	14
20	13	6	4	22	16	14	7	5	23	17	15	8	1	24	18	11	9	2	25	19	12	10	3	21
4	22	20	13	6	5	23	16	14	7	1	24	17	15	8	2	25	18	11	9	3	21	19	12	10
11	9	2	25	18	12	10	3	21	19	13	6	4	22	20	14	7	5	23	16	15	8	1	24	17
23	16	14	7	5	24	17	15	8	1	25	18	11	9	2	21	19	12	10	3	22	20	13	6	4
10	3	21	19	12	6	4	22	20	13	7	5	23	16	14	8	1	24	17	15	9	2	25	18	11
17	15	8	1	24	18	11	9	2	25	19	12	10	3	21	20	13	6	4	22	16	14	7	5	23
1	24	17	15	8	2	25	18	11	9	3	21	19	12	10	4	22	20	13	6	5	23	16	14	7
13	6	4	22	20	14	7	5	23	16	15	8	1	24	17	11	9	2	25	18	12	10	3	21	19
25	18	11	9	2	21	19	12	10	3	22	20	13	6	4	23	16	14	7	5	24	17	15	8	1
7	5	23	16	14	8	1	24	17	15	9	2	25	18	11	10	3	21	19	12	6	4	22	20	13
19	12	10	3	21	20	13	6	4	22	16	14	7	5	23	17	15	8	1	24	18	11	9	2	25
3	21	19	12	10	4	22	20	13	6	5	23	16	14	7	1	24	17	15	8	2	25	18	11	9
15	8	1	24	17	11	9	2	25	18	12	10	3	21	19	13	6	4	22	20	14	7	5	23	16
22	20	13	6	4	23	16	14	7	5	24	17	15	8	1	25	18	11	9	2	21	19	12	10	3
9	2	25	18	11	10	3	21	19	12	6	4	22	20	13	7	5	23	16	14	8	1	24	17	15
16	14	7	5	23	17	15	8	1	24	18	11	9	2	25	19	12	10	3	21	20	13	6	4	22
5	23	16	14	7	1	24	17	15	8	2	25	18	11	9	3	21	19	12	10	4	22	20	13	6
12	10	3	21	19	13	6	4	22	20	14	7	5	23	16	15	8	1	24	17	11	9	2	25	18
24	17	15	8	1	25	18	11	9	2	21	19	12	10	3	22	20	13	6	4	23	16	14	7	5
6	4	22	20	13	7	5	23	16	14	8	1	24	17	15	9	2	25	18	11	10	3	21	19	12
18	11	9	2	25	19	12	10	3	21	20	13	6	4	22	16	14	7	5	23	17	15	8	1	24

In Mathematics Today, Vol 49, 2013, pages 86-87, Ronald P. Nordgren, Brown School of Engineering, Rice University (USA), presents "systematic methods of constructing pandiagonal sudoku squares of order k*k and Knut Vik sudoku squares of order k*k not divisible by 2 or 3". Pandiagonal magic squares are constructed from these squares.

A reprint of this paper, including an unpublished appendix with additional examples, is available at http://arxiv.org/abs/1307.1034

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