Row sums of A296666.

Terms

a(0) =1a(1) =4a(2) =20a(3) =96a(4) =444a(5) =2000a(6) =8840a(7) =38528a(8) =166124a(9) =710256a(10) =3016056a(11) =12736064a(12) =53530840a(13) =224107936a(14) =935062544a(15) =3890018816a(16) =16141765964a(17) =66829954736a(18) =276135664664