a(n) = n$ / A055773(n), where n$ denotes the swinging factorial (A056040).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =4a(7) =4a(8) =2a(9) =18a(10) =36a(11) =36a(12) =12a(13) =12a(14) =24a(15) =360a(16) =90a(17) =90a(18) =20a(19) =20a(20) =4a(21) =84a(22) =168a(23) =168a(24) =28a(25) =700a(26) =1400a(27) =37800a(28) =5400a(29) =5400