Number of 5-ascent sequences of length n that avoid the pattern 00.

Terms

a(0) =1a(1) =1a(2) =5a(3) =25a(4) =115a(5) =485a(6) =1875a(7) =6655a(8) =21755a(9) =65800a(10) =185169a(11) =487763a(12) =1209978a(13) =2843009a(14) =6360875a(15) =13616713a(16) =28008865a(17) =55567799a(18) =106683637a(19) =198787805a(20) =360428177a(21) =637343681a(22) =1101362043a(23) =1863225539a(24) =3090808955a(25) =5034648646a(26) =8063271761a(27) =12711523735a(28) =19745967040