For a given value of "n" > 0, the index "m" in "A"("n", "m") can take values from 0 to "n" − 1. For fixed "n" there is a single permutation which has 0 ascents: ("n", "n" − 1, "n" − 2, ..., 1). There is also a single permutation which has "n" − 1 ascents; this is the rising permutation (1, 2, 3, ..., "n"). Therefore "A"("n", 0) and "A"("n", "n" − 1) are 1 for all values of "n".