a(n) is the unique integer k such that A108951(k) = n!.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =12a(5) =20a(6) =60a(7) =84a(8) =672a(9) =1512a(10) =5040a(11) =7920a(12) =47520a(13) =56160a(14) =157248a(15) =393120a(16) =6289920a(17) =8225280a(18) =37013760a(19) =41368320a(20) =275788800a(21) =579156480a(22) =1820206080a(23) =2203407360a(24) =26440888320a(25) =73446912000a(26) =173601792000a(27) =585906048000