a(n) = T(2*n+1, n+3), T given by A027011.

Terms

a(0) =1a(1) =9a(2) =150a(3) =1085a(4) =5283a(5) =20495a(6) =69007a(7) =212020a(8) =613633a(9) =1708508a(10) =4640978a(11) =12414802a(12) =32903418a(13) =86731043a(14) =227905816a(15) =597838223a(16) =1566763325a(17) =4103989113a(18) =10747219441a(19) =28140274566a(20) =73676929931a(21) =192894712070a(22) =505012447636