A bisection of A162584.

Terms

a(0) =2a(1) =16a(2) =96a(3) =448a(4) =1858a(5) =6896a(6) =23776a(7) =76608a(8) =234432a(9) =684336a(10) =1921472a(11) =5206208a(12) =13679490a(13) =34941120a(14) =87036576a(15) =211822976a(16) =504784704a(17) =1179589728a(18) =2707337056a(19) =6109982400a(20) =13575320320a(21) =29721857904a(22) =64184237216a(23) =136816242816