Row sums of triangle A046521.

Terms

a(0) =1a(1) =3a(2) =13a(3) =61a(4) =295a(5) =1447a(6) =7151a(7) =35491a(8) =176597a(9) =880125a(10) =4390901a(11) =21920913a(12) =109486993a(13) =547018941a(14) =2733608905a(15) =13662695645a(16) =68294088535a(17) =341399727335