a(n) = T(n,2n-10), T given by A027023.

Terms

a(0) =1a(1) =1a(2) =5a(3) =17a(4) =57a(5) =193a(6) =653a(7) =2205a(8) =7417a(9) =24805a(10) =82373a(11) =271437a(12) =887377a(13) =2878509a(14) =9268429a(15) =29636981a(16) =94163769a(17) =297435285a(18) =934521973a(19) =2922073641a(20) =9096981049a(21) =28209178729a(22) =87163760797a(23) =268462020889a(24) =824451264113