Erroneous version of A002689.

Terms

a(0) =1a(1) =6a(2) =8a(3) =180a(4) =32a(5) =10080a(6) =3456a(7) =453600a(8) =115200a(9) =47900160a(10) =71680a(11) =217945728000a(12) =36578304000a(14) =45984153600