Right hand diagonal of triangle A199476.

Terms

a(0) =2a(1) =6a(2) =16a(3) =34a(4) =77a(5) =157a(6) =328a(7) =655a(8) =1309a(9) =2550a(10) =4958a(11) =9462a(12) =17970a(13) =33714a(14) =62858a(15) =116088a(16) =213125a(17) =388243a(18) =703243a(19) =1265577a(20) =2265501a(21) =4032724a(22) =7143593a(23) =12591333a(24) =22094399a(25) =38597179a(26) =67149059a(27) =116350178a(28) =200838270a(29) =345396783