n*A027642(n).

Terms

a(0) =0a(1) =2a(2) =12a(3) =3a(4) =120a(5) =5a(6) =252a(7) =7a(8) =240a(9) =9a(10) =660a(11) =11a(12) =32760a(13) =13a(14) =84a(15) =15a(16) =8160a(17) =17a(18) =14364a(19) =19a(20) =6600a(21) =21a(22) =3036a(23) =23a(24) =65520a(25) =25a(26) =156a(27) =27a(28) =24360a(29) =29