Diagonal sums of number triangle A184883.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =11a(5) =27a(6) =60a(7) =132a(8) =301a(9) =669a(10) =1502a(11) =3370a(12) =7543a(13) =16919a(14) =37912a(15) =84968a(16) =190457a(17) =426841a(18) =956698a(19) =2144238a(20) =4805827a(21) =10771315a(22) =24141588a(23) =54108332a(24) =121272549a(25) =271806901a(26) =609198390a(27) =1365390546a(28) =3060236911a(29) =6858880431