Row sums of A047997.

Terms

a(0) =0a(1) =1a(2) =3a(3) =9a(4) =25a(5) =75a(6) =235a(7) =759a(8) =2521a(9) =8555a(10) =29503a(11) =103129a(12) =364547a(13) =1300819a(14) =4679471a(15) =16952161a(16) =61790441a(17) =226451035a(18) =833918839a(19) =3084255127a(20) =11451630043a(21) =42669225171a(22) =159497648599a(23) =597950875255