Consider the set
S = {1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 13, 14, 15, 16, 17, 18, 19, 23, 24, 25 ... 123456789}
which consists of all positive integers whose digits strictly increase from left to right. This set is finite. What is
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+216 Nov 8, 2021
+28
