Number of skew Dyck paths of semilength n having no peaks at level 1.

A128723

Number of skew Dyck paths of semilength n having no peaks at level 1.

Terms

    a(0) =1a(1) =0a(2) =2a(3) =6a(4) =22a(5) =84a(6) =334a(7) =1368a(8) =5734a(9) =24480a(10) =106086a(11) =465462a(12) =2063658a(13) =9231084a(14) =41610162a(15) =188820726a(16) =861891478a(17) =3954732384a(18) =18230522422a(19) =84390187986a(20) =392120098258

External references