a(n) = A081456(n)^(1/2).

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =12a(5) =36a(6) =120a(7) =240a(8) =720a(9) =2520a(10) =10080a(11) =30240a(12) =110880a(13) =443520a(14) =1814400a(15) =6652800a(16) =26611200a(17) =133056000a(18) =518918400a(19) =2075673600a(20) =10378368000a(21) =58118860800a(22) =261534873600