Number of Dyck paths of semilength n and height exactly 4.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =7a(6) =33a(7) =132a(8) =484a(9) =1684a(10) =5661a(11) =18579a(12) =59917a(13) =190696a(14) =600744a(15) =1877256a(16) =5828185a(17) =17998783a(18) =55342617a(19) =169552428a(20) =517884748a(21) =1577812060a(22) =4796682165a(23) =14555626635a(24) =44100374341a(25) =133436026192a(26) =403279293648