a(n) = sigma(n!).

Terms

a(0) =1a(1) =1a(2) =3a(3) =12a(4) =60a(5) =360a(6) =2418a(7) =19344a(8) =159120a(9) =1481040a(10) =15334088a(11) =184009056a(12) =2217441408a(13) =31044179712a(14) =442487616480