n!, digits ordered, zeros omitted.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =12a(6) =27a(7) =45a(8) =234a(9) =23688a(10) =23688a(11) =136899a(12) =14679a(13) =222678a(14) =112277889a(15) =133466778a(16) =2227888899a(17) =23455667889a(18) =22334567778a(19) =111223445688a(20) =122234466789