T(n,n+1), array T as in A047140.

Terms

a(0) =1a(1) =1a(2) =2a(3) =15a(4) =62a(5) =180a(6) =566a(7) =2419a(8) =9780a(9) =34958a(10) =125068a(11) =491958a(12) =1943862a(13) =7377378a(14) =27781250a(15) =107932937a(16) =422922350a(17) =1637252968a(18) =6306134498a(19) =24545899232a(20) =96073204466a(21) =374915623580