Diagonal sums of number triangle A108359.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =13a(6) =25a(7) =47a(8) =90a(9) =172a(10) =329a(11) =629a(12) =1202a(13) =2294a(14) =4374a(15) =8330a(16) =15847a(17) =30115a(18) =57172a(19) =108434a(20) =205473a(21) =389019a(22) =735927a(23) =1391121a(24) =2627720a(25) =4960134a(26) =9356707a(27) =17639323a(28) =33234036a(29) =62580444