Wilf Class

Two patterns T_1 and T_2 belong to the same Wilf class if |S_n(T_1)|=|S_n(T_2)| for all n, where S_n(T) denotes the set of permutations on {1,...,n} that avoid the pattern T. Two sets having the same Wilf class are said to be Wilf equivalent.

See also

Avoided Pattern, Wilf Equivalent, Permutation Pattern

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Mansour, T. "Permutations Avoiding a Pattern from S_k and at Least Two Patterns from S_3." 31 Jul 2000.

Referenced on Wolfram|Alpha

Wilf Class

Cite this as:

Weisstein, Eric W. "Wilf Class." From MathWorld--A Wolfram Web Resource.

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