Number of up steps in all length n left factors of Dyck paths.

Terms

a(0) =0a(1) =1a(2) =3a(3) =7a(4) =17a(5) =36a(6) =82a(7) =169a(8) =373a(9) =760a(10) =1646a(11) =3334a(12) =7130a(13) =14392a(14) =30500a(15) =61429a(16) =129293a(17) =260016a(18) =544342a(19) =1093546a(20) =2279470a(21) =4575736a(22) =9504188a(23) =19067162a(24) =39486402a(25) =79180816a(26) =163561932a(27) =327866764a(28) =675791828a(29) =1354258096