n-th diagonal sum of right justified array T given by A027960.

Terms

a(0) =1a(1) =1a(2) =4a(3) =6a(4) =10a(5) =18a(6) =29a(7) =47a(8) =78a(9) =126a(10) =204a(11) =332a(12) =537a(13) =869a(14) =1408a(15) =2278a(16) =3686a(17) =5966a(18) =9653a(19) =15619a(20) =25274a(21) =40894a(22) =66168a(23) =107064a(24) =173233a(25) =280297a(26) =453532a(27) =733830a(28) =1187362a(29) =1921194