T(2n+1,n+4), T given by A026747.

Terms

a(0) =1a(1) =10a(2) =67a(3) =380a(4) =1976a(5) =9771a(6) =46845a(7) =220232a(8) =1022498a(9) =4710021a(10) =21593848a(11) =98750485a(12) =451158834a(13) =2061525163a(14) =9429060852a(15) =43193760271a(16) =198255105055a(17) =912011899565