login
A353869
Squarefree numbers k such that the Carmichael function A002322(k) divides the Dedekind psi A001615(k).
3
1, 2, 3, 6, 14, 15, 30, 35, 42, 65, 70, 78, 105, 119, 130, 182, 190, 195, 210, 238, 255, 357, 370, 377, 390, 418, 455, 510, 546, 570, 595, 663, 714, 754, 910, 969, 1045, 1110, 1118, 1131, 1190, 1254, 1326, 1330, 1365, 1547, 1558, 1615, 1785, 1885, 1887, 1938, 2090, 2190, 2261, 2262, 2470, 2590, 2639, 2730
OFFSET
1,2
COMMENTS
If s,t are terms, then so is lcm(s,t); in particular, if s,t are coprime, then s*t is also a term. Primitive squarefree terms are listed in A353871.
MATHEMATICA
psi[1] = 1; psi[n_] := n * Times @@ (1 + 1/Transpose[FactorInteger[n]][[1]]); Select[Range[3000], SquareFreeQ[#] && Divisible[psi[#], CarmichaelLambda[#]] &] (* Amiram Eldar, May 09 2022 *)
CROSSREFS
Intersection of A005117 and A353868.
Sequence in context: A030733 A335288 A122839 * A258077 A121556 A123041
KEYWORD
nonn,mult
AUTHOR
Max Alekseyev, May 08 2022
STATUS
approved