Alternating row sums of triangle A291844.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =18a(5) =55a(6) =171a(7) =538a(8) =1708a(9) =5461a(10) =17560a(11) =56728a(12) =183973a(13) =598597a(14) =1953145a(15) =6388376a(16) =20939664a(17) =68764283a(18) =226192964a(19) =745146462a(20) =2458020664a(21) =8118111977a(22) =26841209903a(23) =88835163150a(24) =294284206183a(25) =975699571009