ASKSAGE: Sage Q&A Forum - Individual question feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Sat, 19 Dec 2015 16:54:27 -0600Does Sage has an inverse totient function command?https://ask.sagemath.org/question/31704/does-sage-has-an-inverse-totient-function-command/I know about euler_phi(n), but is there a command where I can a get a list or some sort of other collection for all those values where n = euler_phi(f(n))? Sat, 19 Dec 2015 14:36:59 -0600https://ask.sagemath.org/question/31704/does-sage-has-an-inverse-totient-function-command/Answer by kcrisman for <p>I know about euler_phi(n), but is there a command where I can a get a list or some sort of other collection for all those values where n = euler_phi(f(n))? </p>
https://ask.sagemath.org/question/31704/does-sage-has-an-inverse-totient-function-command/?answer=31706#post-id-31706This seems to be [rather nontrivial](http://math.stackexchange.com/questions/265397/inversion-of-the-euler-totient-function) though I guess something like one of the many suggestions there could be implemented... at first I thought you mean the [Dirichlet inverse](https://oeis.org/A023900/internal) but I guess not.Sat, 19 Dec 2015 16:54:27 -0600https://ask.sagemath.org/question/31704/does-sage-has-an-inverse-totient-function-command/?answer=31706#post-id-31706