a(n) = Sum_{j=0..n} T(n,j), T given by A026736.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =17a(5) =34a(6) =73a(7) =146a(8) =314a(9) =628a(10) =1350a(11) =2700a(12) =5798a(13) =11596a(14) =24872a(15) =49744a(16) =106573a(17) =213146a(18) =456169a(19) =912338a(20) =1950697a(21) =3901394a(22) =8334539a(23) =16669078a(24) =35582783a(25) =71165566a(26) =151809737a(27) =303619474a(28) =647279131a(29) =1294558262