|
|
A275998
|
|
Numbers n such that phi(n^2-1) = phi(n^2+1).
|
|
0
|
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
EXAMPLE
|
3 is a term because phi(3^2-1) = phi(3^2+1).
|
|
MATHEMATICA
|
Select[Range@10000000, EulerPhi@(#^2 - 1) == EulerPhi[#^2 + 1] &] (* Vincenzo Librandi, Aug 18 2016 *)
|
|
PROG
|
(PARI) isok(n) = eulerphi(n^2-1) == eulerphi(n^2+1); \\ Michel Marcus, Aug 16 2016
(Magma) [n: n in [2..100000] | EulerPhi(n^2-1) eq EulerPhi(n^2+1)]; // Vincenzo Librandi, Aug 18 2016
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|