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Today's number is the maximum number of pieces that a (circular) pancake can be cut into with 17 straight cuts.
If the numbers 1 to 7 are arranged 7,1,2,6,3,4,5 then each number is either larger than or a factor of the number before it.
How many ways can the numbers 1 to 7 be arranged to that each number is either larger than or a factor of the number before it?