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Omni-MATH / Von Neumann's Poker: The first step in Von Neumann's game is selecting a random…

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Von Neumann's Poker: The first step in Von Neumann's game is selecting a random number on [0,1][0,1]. To generate this number, Chebby uses the factorial base: the number 0.A1A2A3A4…0 . A_{1} A_{2} A_{3} A_{4} \ldots stands for ∑n=0∞An(n+1)!\sum_{n=0}^{\infty} \frac{A_{n}}{(n+1)!}, where each AnA_{n} is an integer between 0 and nn, inclusive. Chebby has an infinite number of cards labeled 0,1,2,…0, 1, 2, \ldots. He begins by putting cards 00 and 11 into a hat and drawing randomly to determine A1A_{1}. The card assigned A1A_{1} does not get reused. Chebby then adds in card 2 and draws for A2A_{2}, and continues in this manner to determine the random number. At each step, he only draws one card from two in the hat. Unfortunately, this method does not result in a uniform distribution. What is the expected value of Chebby's final number?
Plain-text mathematical notation (without MathML)
Von Neumann's Poker: The first step in Von Neumann's game is selecting a random number on [0,1]. To generate this number, Chebby uses the factorial base: the number 0.A₁A₂A₃A₄… stands for ∑_(n=0)^(∞)(A_(n))/((n+1)!), where each A_(n) is an integer between 0 and n, inclusive. Chebby has an infinite number of cards labeled 0,1,2,…. He begins by putting cards 0 and 1 into a hat and drawing randomly to determine A₁. The card assigned A₁ does not get reused. Chebby then adds in card 2 and draws for A₂, and continues in this manner to determine the random number. At each step, he only draws one card from two in the hat. Unfortunately, this method does not result in a uniform distribution. What is the expected value of Chebby's final number?
Original LaTeX notation
Von Neumann's Poker: The first step in Von Neumann's game is selecting a random number on $[0,1]$. To generate this number, Chebby uses the factorial base: the number $0 . A_{1} A_{2} A_{3} A_{4} \ldots$ stands for $\sum_{n=0}^{\infty} \frac{A_{n}}{(n+1)!}$, where each $A_{n}$ is an integer between 0 and $n$, inclusive. Chebby has an infinite number of cards labeled $0, 1, 2, \ldots$. He begins by putting cards $0$ and $1$ into a hat and drawing randomly to determine $A_{1}$. The card assigned $A_{1}$ does not get reused. Chebby then adds in card 2 and draws for $A_{2}$, and continues in this manner to determine the random number. At each step, he only draws one card from two in the hat. Unfortunately, this method does not result in a uniform distribution. What is the expected value of Chebby's final number?

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