Denominator of Sum_{k=1..n} 1/phi(k).

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =4a(5) =4a(6) =12a(7) =6a(8) =3a(9) =12a(10) =60a(11) =15a(12) =60a(13) =60a(14) =120a(15) =30a(16) =240a(17) =80a(18) =720a(19) =720a(20) =720a(21) =720a(22) =7920a(23) =7920a(24) =1584a(25) =1584a(26) =1584a(27) =1584a(28) =11088a(29) =11088