Problem 59861. List the ways to write 1/n as the sum of two unit fractions

ChrisR

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Cody Problem 59841 involved counting the ways that  can be written as the sum of two unit fractions (those with a numerator of 1). For example, the number 1/2 can be written as 1/3+1/6 and 1/4+1/4, and the number 1/9 can be written as 1/18+1/18, 1/12+1/36, and 1/10+1/90. 
Write a function to list the ways  can be written as the sum of two unit fractions. The output should be a two-column matrix of the denominator pairs with the smaller denominator in the first column and the larger in the second. The values in the first column should be sorted in increasing order. For example, if n = 9, then the output should be [10 90; 12 36; 18 18].