Generating trees and forbidden subsequences
The author discusses an enumerative technique called generating trees which was introduced in the study of Baxter permutations. He applies the technique to some other classes of permutations with forbidden subsequences. The author also rederives some known results, e.g., \(S_n(123,231)=2^n\) and \(S_n(123,132,213)= F_n\), and adds several new ones: \(S_n(123,3241)\), \(S_n(123,3214)\), and \(S_n(123,2143)\). Finally, the author argues for the broader use of generating trees in combinatorial enumeration.
scientific article; zbMATH DE number 935388