Number of skew Dyck paths of semilength n having no ascents of length 1.

Terms

a(0) =1a(1) =0a(2) =2a(3) =4a(4) =14a(5) =44a(6) =150a(7) =520a(8) =1850a(9) =6696a(10) =24602a(11) =91500a(12) =343846a(13) =1303572a(14) =4979822a(15) =19150352a(16) =74075890a(17) =288022160a(18) =1125076210a(19) =4413061972a(20) =17375007294a(21) =68641377980a(22) =272014578822