Number of Grand Dyck-Motzkin paths of length n.

Terms

a(0) =1a(1) =1a(2) =3a(3) =6a(4) =16a(5) =38a(6) =100a(7) =254a(8) =674a(9) =1772a(10) =4760a(11) =12783a(12) =34745a(13) =94692a(14) =260040a(15) =716546a(16) =1984984a(17) =5517179a(18) =15396331a(19) =43094834a(20) =121008580a(21) =340686763a(22) =961686971a(23) =2720893669a(24) =7715273753a(25) =21921047638a(26) =62401862460a(27) =177948692666a(28) =508289340032