a(n) = numerators of n!/10^n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =3a(5) =3a(6) =9a(7) =63a(8) =63a(9) =567a(10) =567a(11) =6237a(12) =18711a(13) =243243a(14) =1702701a(15) =5108103a(16) =5108103a(17) =86837751a(18) =781539759a(19) =14849255421a(20) =14849255421a(21) =311834363841