Partial products of A003188 (Gray code).

Terms

a(0) =1a(1) =1a(2) =3a(3) =6a(4) =36a(5) =252a(6) =1260a(7) =5040a(8) =60480a(9) =786240a(10) =11793600a(11) =165110400a(12) =1651104000a(13) =18162144000a(14) =163459296000