T(n,n-2), array T given by A047000.

Terms

a(0) =1a(1) =1a(2) =4a(3) =7a(4) =30a(5) =143a(6) =585a(7) =2420a(8) =9690a(9) =38779a(10) =153769a(11) =608925a(12) =2404100a(13) =9484317a(14) =37378622a(15) =147270615a(16) =580094570a(17) =2284987355a(18) =9001081353a(19) =35463025663a(20) =139747015800a(21) =550824207900