Numbers k such that d(k) (number of divisors) divides phi(k) (Euler function) divides sigma(k) (sum of divisors).

A020493

Numbers k such that d(k) (number of divisors) divides phi(k) (Euler function) divides sigma(k) (sum of divisors).

Terms

    a(0) =1a(1) =3a(2) =15a(3) =30a(4) =35a(5) =56a(6) =70a(7) =78a(8) =105a(9) =140a(10) =168a(11) =190a(12) =210a(13) =248a(14) =264a(15) =357a(16) =420a(17) =570a(18) =616a(19) =630a(20) =714a(21) =744a(22) =812a(23) =840a(24) =910a(25) =1045a(26) =1240a(27) =1485a(28) =1672a(29) =1848

External references