Row sums of triangle in A081720.

Terms

a(0) =1a(1) =4a(2) =15a(3) =83a(4) =561a(5) =6332a(6) =88086a(7) =1561008a(8) =31966485a(9) =746278033a(10) =19441692751a(11) =559268543516