a(n) is the least integer k such that sigma(sigma(k)) >= n*k where sigma is A000203, the sum of divisors.

A327630

a(n) is the least integer k such that sigma(sigma(k)) >= n*k where sigma is A000203, the sum of divisors.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =6a(4) =24a(5) =24a(6) =24a(7) =60a(8) =120a(9) =480a(10) =540a(11) =1560a(12) =2520a(13) =10920a(14) =27720a(15) =30240a(16) =191520a(17) =360360a(18) =360360a(19) =3243240a(20) =5765760a(21) =28828800a(22) =109549440a(23) =438197760a(24) =766846080a(25) =3834230400a(26) =9081072000a(27) =32974381440a(28) =147516969600a(29) =880887047040

External references