Denominators of Sum_{k=1..n} 1/lcm(n,k).

Terms

a(0) =1a(1) =1a(2) =6a(3) =6a(4) =60a(5) =60a(6) =140a(7) =420a(8) =2520a(9) =2520a(10) =27720a(11) =27720a(12) =360360a(13) =360360a(14) =72072a(15) =360360a(16) =12252240a(17) =12252240a(18) =77597520a(19) =46558512a(20) =25865840a(21) =33256080a(22) =118982864a(23) =5354228880a(24) =8923714800a(25) =3824449200a(26) =80313433200a(27) =80313433200