Diagonal sums of A107267, viewed as a number triangle.

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =3a(5) =6a(6) =16a(7) =44a(8) =136a(9) =457a(10) =1669a(11) =6547a(12) =27334a(13) =120465a(14) =557094a(15) =2692528a(16) =13564940a(17) =71102869a(18) =387132791a(19) =2185813423a(20) =12775466408a(21) =77154694819a(22) =480630407368