a(n) = A027052(n, 2n-10).

Terms

a(0) =1a(1) =1a(2) =3a(3) =11a(4) =37a(5) =125a(6) =423a(7) =1429a(8) =4811a(9) =16111a(10) =53589a(11) =176905a(12) =579407a(13) =1882943a(14) =6073469a(15) =19452705a(16) =61900375a(17) =195799527a(18) =615978629a(19) =1928297807a(20) =6009527345a(21) =18653079889a(22) =57686469763a(23) =177812890843a(24) =546456642501