Counting occurrences of 3412 in an involution

Abstract

We study the generating function for the number of involutions on $n$ letters containing exactly $r\gs0$ occurrences of 3412. It is shown that finding this function for a given $r$ amounts to a routine check of all involutions on $2r+1$ letters.

12 pages, 4 figures

References in corpus (2)

• Restricted 3412-Avoiding Involutions: Continued Fractions, Chebyshev Polynomials and Enumerations
• Involutions Restricted by 3412, Continued Fractions, and Chebyshev Polynomials