Diagonal sums of the Riordan matrix A104259.

Terms

a(0) =1a(1) =2a(2) =6a(3) =19a(4) =66a(5) =244a(6) =946a(7) =3801a(8) =15697a(9) =66234a(10) =284339a(11) =1237983a(12) =5453611a(13) =24263355a(14) =108865901a(15) =492051006a(16) =2238220336a(17) =10238568080a(18) =47070014643a(19) =217363784060