Counting Occurrences of 3412 in an Involution
نویسنده
چکیده
We study the generating function for the number of involutions on n letters containing exactly r ≥ 0 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. 2000 Mathematics Subject Classification: Primary 05A05, 05A15; Secondary 05C90
منابع مشابه
Ja n 20 04 Involutions Restricted by 3412 , Continued Fractions , and Chebyshev Polynomials
We study generating functions for the number of involutions, even involutions, and odd involutions in Sn subject to two restrictions. One restriction is that the involution avoid 3412 or contain 3412 exactly once. The other restriction is that the involution avoid another pattern τ or contain τ exactly once. In many cases we express these generating functions in terms of Chebyshev polynomials o...
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