Denominator of sum of reciprocals of numbers less than n that do not divide n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =12a(5) =20a(6) =20a(7) =70a(8) =840a(9) =504a(10) =2520a(11) =27720a(12) =27720a(13) =51480a(14) =360360a(15) =180180a(16) =720720a(17) =1361360a(18) =4084080a(19) =77597520a(20) =15519504a(21) =470288a(22) =5173168a(23) =356948592a(24) =1784742960a(25) =686439600a(26) =26771144400a(27) =80313433200a(28) =80313433200