Diagonal sums of number triangle A119308.

Terms

a(0) =1a(1) =2a(2) =4a(3) =9a(4) =20a(5) =45a(6) =103a(7) =238a(8) =555a(9) =1305a(10) =3090a(11) =7362a(12) =17637a(13) =42460a(14) =102670a(15) =249246a(16) =607256a(17) =1484343a(18) =3639094a(19) =8946260a(20) =22048771a(21) =54467577a(22) =134842844a(23) =334493154a(24) =831296965a(25) =2069573632a(26) =5160747114a(27) =12888640503a(28) =32234749938a(29) =80728619175