Numbers n such that denominator(sigma(sigma(n))/n) = denominator(sigma(sigma(s))/s) where s = sigma(n).

A275321

Numbers n such that denominator(sigma(sigma(n))/n) = denominator(sigma(sigma(s))/s) where s = sigma(n).

Terms

    a(0) =1a(1) =6a(2) =8a(3) =15a(4) =24a(5) =28a(6) =60a(7) =168a(8) =512a(9) =1023a(10) =1536a(11) =4092a(12) =10752a(13) =12600a(14) =14040a(15) =18564a(16) =24384a(17) =29127a(18) =47360a(19) =57120a(20) =89408a(21) =116508a(22) =306306a(23) =331520a(24) =343976a(25) =687952a(26) =932064a(27) =1556480a(28) =1571328a(29) =1980342

External references