Diagonal sums of A107111, viewed as a number triangle.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =11a(6) =24a(7) =52a(8) =125a(9) =307a(10) =809a(11) =2190a(12) =6249a(13) =18348a(14) =56016a(15) =176272a(16) =571113a(17) =1906091a(18) =6517283a(19) =22879944a(20) =82144248a(21) =301617448a(22) =1131401427a(23) =4327790902a(24) =16886037207a(25) =67073179408a(26) =271242546501