Number of down/up (initially descending) compositions of n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =2a(5) =4a(6) =6a(7) =9a(8) =14a(9) =23a(10) =35a(11) =55a(12) =87a(13) =136a(14) =214a(15) =337a(16) =528a(17) =830a(18) =1306a(19) =2051a(20) =3223a(21) =5067a(22) =7962a(23) =12512a(24) =19667a(25) =30908a(26) =48574a(27) =76343a(28) =119982a(29) =188565