T(n,n-1), array T as in A047110.

Terms

a(0) =1a(1) =2a(2) =5a(3) =10a(4) =29a(5) =164a(6) =534a(7) =1839a(8) =7813a(9) =28888a(10) =106712a(11) =423250a(12) =1621048a(13) =6175114a(14) =24116312a(15) =93457176a(16) =361166949a(17) =1408515216a(18) =5488264319a(19) =21368029926a(20) =83497729588a(21) =326481132377