a(n) is the sum of the divisors of n!+1.

Terms

a(0) =3a(1) =3a(2) =4a(3) =8a(4) =31a(5) =133a(6) =832a(7) =5113a(8) =41044a(9) =388800a(10) =3958704a(11) =39916802a(12) =518682390a(13) =6302045232a(14) =90968651712