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A328950
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Numerators for the "Minimum-Redundancy Code" card problem.
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0
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0, 3, 9, 19, 33, 51, 74, 102, 135, 173, 216, 264, 318, 378, 444, 516, 594, 678, 768, 864, 966, 1074, 1188, 1308, 1435, 1569, 1710, 1858, 2013, 2175, 2344, 2520, 2703, 2893, 3090, 3294, 3505, 3723, 3948, 4180, 4419, 4665, 4918, 5178, 5445, 5719, 6000, 6288, 6584, 6888, 7200, 7520, 7848
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OFFSET
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1,2
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COMMENTS
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Given a deck of cards consisting of one 1, two 2's, three 3's, ..., n n's, what's the best average number of yes-or-no questions needed to ask to determine a randomly drawn card? The answer is the above sequence divided by the number of cards (A000217).
The problem can be solved using Huffman codes.
This problem was popularized in Martin Gardner's Scientific American "Mathematical Games" column, and was included in his book "My Best Mathematical and Logic Puzzles".
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REFERENCES
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Gardner, M. (1995). My best mathematical and logic puzzles. New York: Dover Publications Inc, p29, puzzle #52 "Playing Twenty Questions when Probability Values Are Known"
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LINKS
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EXAMPLE
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For n=2, there are 3 cards, so a(2)/3 = 3/3 = 1 question is needed on average.
For n=3, there are 6 cards, so a(3)/6 = 9/6 = 1.5 questions are needed on average.
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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STATUS
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approved
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