Central terms of triangle A103284.

Terms

a(0) =1a(1) =1a(2) =3a(3) =9a(4) =30a(5) =102a(6) =352a(7) =1240a(8) =4443a(9) =16112a(10) =58900a(11) =216727a(12) =801880a(13) =2982327a(14) =11147622a(15) =41854916a(16) =157805863a(17) =597307573a(18) =2268487476a(19) =8639848112a(20) =32999949539a(21) =126498330700a(22) =485441076004