I learned something in R today thanks to Le Monde mathematical puzzle: A two-player game consists in A picking a number n between 1 and 10 and B and A successively choosing and applying one of three transforms to the current value of n n=n+1, n=3n, n=4n, starting with B, until n is larger than […]

## Search Results

## Le Monde puzzle [#875]

July 12, 2014## Le Monde puzzle [#872]

June 28, 2014An “mildly interesting” Le Monde mathematical puzzle that eventually had me running R code on a cluster: Within the set {1,…,56}, take 12 values at random, x1,…,x12. Is it always possible to pick two pairs from those 12 balls such that their sums are equal? Indeed, while exhaustive search cannot reach the size of the […]

## Le Monde puzzle [#868]

June 1, 2014Another permutation-based Le Monde mathematical puzzle: Given the integers 1,…n, a “perfect” combination is a pair (i,j) of integers such that no other pair enjoys the same sum. For n=33, what is the maximum of perfect combinations one can build? And for n=214? A rather straightforward problem, or so it seemed: take the pairs (2m,2m+1), their […]

## Le Monde puzzle [#865]

May 6, 2014A Le Monde mathematical puzzle in combinatorics: Given a permutation σ of {1,…,5}, if σ(1)=n, the n first values of σ are inverted. If the process is iterated until σ(1)=1, does this always happen and if so what is the maximal number of iterations? Solve the same question for the set {1,…,2014}. I ran the following basic R […]