OFFSET
1,2
COMMENTS
LINKS
user142929, A definition related to pseudoprimes and the Dedekind psi function, MathOverflow, 2022.
MATHEMATICA
psi[1] = 1; psi[n_] := n * Times @@ (1 + 1/Transpose[FactorInteger[n]][[1]]); Select[Range[216], Divisible[psi[#], CarmichaelLambda[#]] &] (* Amiram Eldar, May 09 2022 *)
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Max Alekseyev, May 08 2022
STATUS
approved