T(n,n+1), array T as in A047060.

Terms

a(0) =1a(1) =1a(2) =2a(3) =7a(4) =23a(5) =99a(6) =377a(7) =1490a(8) =5758a(9) =21963a(10) =85169a(11) =329731a(12) =1282267a(13) =4989115a(14) =19399068a(15) =75590876a(16) =294873228a(17) =1151946859a(18) =4504965687a(19) =17630031637a(20) =69055693242a(21) =270701719946