## Le Monde puzzle [#843]

December 7, 2013

A Le Monde mathematical puzzle of moderate difficulty: How many binary quintuplets (a,b,c,d,e) can be found such that any pair of quintuplets differs by at least two digits? I solved it by the following R code that iteratively eliminates quintuplets that are not different enough from the first ones, for a random order of the […]

## Le Monde puzzle [#842]

November 30, 2013

An easily phrased (and solved?) Le Monde mathematical puzzle that does not [really] require an R code: The five triplets A,B,C,D,E are such that and Given that find the five triplets. Adding up both sets of equations shows everything solely depends upon E1… So running an R code that checks for all possible values of […]

## Le Monde puzzle [#840]

November 23, 2013

Another number theory Le Monde mathematical puzzles: Find 2≤n≤50 such that the sequence {1,…,n} can be permuted into a sequence such that the sum of two consecutive terms is a prime number.  Now this is a problem with an R code solution: which returns the solution as and so it seems there is no solution beyond N=12… […]

## Le Monde puzzle [#839]

November 16, 2013

A number theory Le Monde mathematical puzzle whose R coding is not really worth it (and which rings a bell of a similar puzzle in the past, puzzle I cannot trace…): The set Ξ is made of pairs of integers (x,y) such that (i) both x and y are written as a sum of two squared integers (i.e., are […]

## Le Monde puzzle [#838]

November 2, 2013

Another one of those Le Monde mathematical puzzles which wording is confusing to me: The 40 members of the Academy vote for two prizes. [Like the one recently attributed to my friend and coauthor Olivier Cappé!] Once the votes are counted for both prizes, it appears that the total votes for each of the candidates […]