First differences of A061396.

Terms

a(0) =0a(1) =1a(2) =4a(3) =14a(4) =53a(5) =208a(6) =843a(7) =3494a(8) =14769a(9) =63378a(10) =275480a(11) =1210213a(12) =5365307a(13) =23973429a(14) =107853409a(15) =488137798a(16) =2221048540a(17) =10153825751a(18) =46617145752a(19) =214844862927a(20) =993601026038