Journal of Integer Sequences, Vol. 13 (2010), Article 10.8.7

Baron Münchhausen's Sequence

Tanya Khovanova
Department of Mathematics
Massachusetts Institute of Technology
77 Massachusetts Avenue
Cambridge, MA 02139

Konstantin Knop
Youth Mathematics School
St. Petersburg State University
Tallinskaya 21
195112 St. Petersburg
Russian Federation

Alexey Radul
Computer Science and Artificial Intelligence Laboratory
Massachusetts Institute of Technology
32 Vassar Street
Cambridge, MA 02139


We investigate a coin-weighing puzzle that appeared in the all-Russian Mathematics Olympiad in 2000. The methods of analysis differ from classical coin-weighing puzzles. We generalize the puzzle by varying the number of participating coins, and deduce a complete solution. Perhaps surprisingly, the objective can be achieved in no more than two weighings regardless of the number of coins involved.

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(Concerned with sequence A020756.)

Received March 14 2010; revised version received August 23 2010. Published in Journal of Integer Sequences, September 3 2010.

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