a(n) = n!/LCM{1, C(n-1,1), C(n-2,2), ..., C(n-[ n/2 ],[ n/2 ])}.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =8a(5) =10a(6) =24a(7) =84a(8) =192a(9) =432a(10) =2880a(11) =15840a(12) =34560a(13) =224640a(14) =483840a(15) =3628800a(16) =116121600a(17) =493516800a(18) =1045094400a(19) =9928396800a(20) =20901888000a(21) =219469824000