Row sums of table A164341.

Terms

a(0) =1a(1) =4a(2) =9a(3) =27a(4) =61a(5) =185a(6) =469a(7) =1456a(8) =4368a(9) =14720a(10) =50800a(11) =190149a(12) =735451a(13) =3001161a(14) =12659652a(15) =55462967a(16) =250186665a(17) =1163114375a(18) =5548002866a(19) =27151477487a(20) =135968479892a(21) =696511087808