Diagonal sums of number triangle A109244.

Terms

a(0) =1a(1) =1a(2) =5a(3) =15a(4) =54a(5) =193a(6) =708a(7) =2627a(8) =9846a(9) =37178a(10) =141223a(11) =539047a(12) =2065813a(13) =7943706a(14) =30634329a(15) =118433821a(16) =458867295a(17) =1781267606a(18) =6926405025a(19) =26973935420a(20) =105189301334a(21) =410707352869