a(n) = gcd(n!, n!*(1 + 1/2 + 1/3 + ... + 1/n)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =2a(5) =36a(6) =36a(7) =144a(8) =144a(9) =1440a(10) =1440a(11) =17280a(12) =17280a(13) =241920a(14) =3628800a(15) =29030400a(16) =29030400a(17) =1567641600a(18) =1567641600a(19) =156764160000