Number of permutations of [2n] having exactly n alternating up/down runs where the first run is not a down run.

A360426

Number of permutations of [2n] having exactly n alternating up/down runs where the first run is not a down run.

Terms

    a(0) =1a(1) =1a(2) =6a(3) =118a(4) =4788a(5) =325446a(6) =33264396a(7) =4766383420a(8) =911323052520

External references