Largest unitary square divisor of n!.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =144a(7) =144a(8) =9a(9) =81a(10) =518400a(11) =518400a(12) =25600a(13) =25600a(14) =1225a(15) =35721a(16) =35721a(17) =35721a(18) =21069103104a(19) =21069103104a(21) =163840000a(22) =75625a(23) =75625a(27) =319515625a(28) =767157015625a(29) =767157015625