Inversion sequences and signed permutations

A signed inversion sequence of length n is a sequence of integers (Formula Present), where (Formula Present) for every i ∈ {0, 1, …, n − 1}. For a set of signed patterns B, let Ī_n(B) be the set of signed inversion sequences of length n that avoid all the signed patterns from B. We say that two sets of signed patterns B and C are Wilf-equivalent if |Ī_n(B)| = |Ī_n(C)| for every n ≥ 0. In this paper, by generating trees, we show that the number of Wilf-equivalences among singles of a length-2 signed pattern is 3 and the number of Wilf-equivalences among pairs of a length-2 signed patterns is 30.