Number of LDU's in all skew Dyck paths of semilength n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =10a(6) =69a(7) =412a(8) =2291a(9) =12244a(10) =63886a(11) =328256a(12) =1669363a(13) =8429384a(14) =42349096a(15) =211982828a(16) =1058244079a(17) =5272285552a(18) =26227527576a(19) =130323237088a(20) =647013004499