Number of Dyck paths of semilength n such that each level has exactly six peaks or no peaks.

Terms

a(0) =1a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =1a(8) =6a(9) =16a(10) =31a(11) =56a(12) =102a(13) =179a(14) =426a(15) =1490a(16) =5164a(17) =18715a(18) =73281a(19) =253183a(20) =741420a(21) =1915072a(22) =4599352a(23) =10845192a(24) =26990806a(25) =76446936a(26) =251549461a(27) =918616924a(28) =3497341145a(29) =13161267180