On pairings of the first \(2n\) natural numbers. (English) Zbl 0228.10012
Online Encyclopedia of Integer Sequences:
Number of pairings {(b(1), c(1)), (b(2), c(2)), ..., (b(n), c(n))} of the first 2n positive integers satisfying b(i) < c(i) and such that the 2n numbers c(i)+b(i) and c(i)-b(i) are all distinct.Number of solutions to non-attacking reflecting queens problem.