a(n) = A025487(n) * A324576(n) = A025487(n) * A276086(A025487(n)).

Terms

a(0) =2a(1) =6a(2) =36a(3) =30a(4) =120a(5) =300a(6) =3600a(7) =15000a(8) =210a(9) =672a(10) =1260a(11) =42000a(12) =2940a(13) =28224a(14) =88200a(15) =164640a(16) =288120a(17) =4609920a(18) =216090000a(19) =21176820a(20) =564715200a(21) =2310a(22) =11880a(23) =18480a(24) =4435200a(25) =19404000a(26) =66555720a(27) =44370480000a(28) =50820a(29) =1306800