Numbers n such that (n, sigma(n), tau(n)) lies on a sphere with integral radius centered at the origin, i.e., n^2 + sigma(n)^2 + tau(n)^2 is a square.
A243455
Numbers n such that (n, sigma(n), tau(n)) lies on a sphere with integral radius centered at the origin, i.e., n^2 + sigma(n)^2 + tau(n)^2 is a square.
Terms
- a(0) =6a(1) =61a(2) =2089a(3) =3606a(4) =18585a(5) =28710a(6) =70981a(7) =121374a(8) =176529a(9) =520320a(10) =970783a(11) =62788800a(12) =114682878a(13) =144653952a(14) =174635334a(15) =182054895a(16) =3857228169a(17) =4349012190a(18) =15994971740a(19) =17587660602a(20) =22842677823a(21) =65183331200a(22) =66928439760
External references
- oeis: A243455