T(n,n+1), array T given by A047000.

Terms

a(0) =1a(1) =2a(2) =5a(3) =16a(4) =53a(5) =186a(6) =665a(7) =2430a(8) =8981a(9) =33556a(10) =126300a(11) =478468a(12) =1821677a(13) =6965726a(14) =26730639a(15) =102895388a(16) =397130997a(17) =1536321264a(18) =5955477230a(19) =23128018490a(20) =89962619148a(21) =350442078972