Integers of the form (Product_{i=1..k} sigma(i))/(Product_{i=1..k} phi(i)) = A066780(k)/A001088(k).
A066986
Integers of the form (Product_{i=1..k} sigma(i))/(Product_{i=1..k} phi(i)) = A066780(k)/A001088(k).
Terms
- a(0) =1a(1) =3a(2) =6a(3) =21a(4) =189a(5) =252a(6) =945a(7) =361179a(8) =1083537
External references
- oeis: A066986