Numbers k such that sigma_3(k) is divisible by the square of phi(k).

A091285

Numbers k such that sigma_3(k) is divisible by the square of phi(k).

Terms

    a(0) =1a(1) =2a(2) =3a(3) =6a(4) =14a(5) =42a(6) =3810a(7) =318990a(8) =13243560a(9) =1108809240a(10) =1719507048a(11) =25330080090a(12) =271984504290

External references