MathDB
faro shuffle 8 times =Id (VJIMC 2014 1.2)

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May 20, 2021
combinatorics

Problem Statement

We have a deck of 2n2n cards. Each shuffling changes the order from a1,a2,…,an,b1,b2,…,bna_1,a_2,\ldots,a_n,b_1,b_2,\ldots,b_n to a1,b1,a2,b2,…,an,bna_1,b_1,a_2,b_2,\ldots,a_n,b_n. Determine all even numbers 2n2n such that after shuffling the deck 88 times the original order is restored.
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