a(n) = denominator of Sum_{d|n} 1/sigma(d).

Terms

a(0) =1a(1) =3a(2) =4a(3) =21a(4) =6a(5) =3a(6) =8a(7) =35a(8) =52a(9) =9a(10) =12a(11) =84a(12) =14a(13) =2a(14) =24a(15) =1085a(16) =18a(17) =13a(18) =20a(19) =18a(20) =32a(21) =9a(22) =24a(23) =14a(24) =186a(25) =7a(26) =520a(27) =56a(28) =30a(29) =18