Number of Motzkin trees that are a "uniquely typable skeleton".

Terms

a(0) =0a(1) =1a(2) =0a(3) =0a(4) =2a(5) =0a(6) =1a(7) =7a(8) =1a(9) =13a(10) =34a(11) =20a(12) =100a(13) =226a(14) =234a(15) =853a(16) =1877a(17) =2650a(18) =8128a(19) =18116a(20) =30483a(21) =85713