a(n) = 2^(2n+1)*(2n+1)!.A067626a(n) = 2^(2n+1)*(2n+1)!.Terms a(0) =2a(1) =48a(2) =3840a(3) =645120a(4) =185794560a(5) =81749606400External referencesoeis: A067626