a(n) = n! * Sum_{k=1..n} k/floor(n/k).

Terms

a(0) =1a(1) =5a(2) =32a(3) =198a(4) =1584a(5) =12480a(6) =122520a(7) =1214640a(8) =14011200a(9) =166924800a(10) =2274894720a(11) =31135104000a(12) =485667705600