Denominator of Cotesian number C(n,1).

Terms

a(0) =2a(1) =3a(2) =8a(3) =45a(4) =96a(5) =35a(6) =17280a(7) =14175a(8) =89600a(9) =149688a(10) =29030400a(11) =79625a(12) =402361344000a(13) =312741000a(14) =229605376a(15) =488462349375a(17) =50697046400