OFFSET
1,1
COMMENTS
Composite numbers k for which A340082(k) = 1.
Are there any other non-powers of 2 apart from 9, 81, 180225 (= 3^4 * 5^2 * 89) present?
If there are no squarefree numbers in this sequence, then Lehmer's Totient problem has no composite solutions.
LINKS
MATHEMATICA
f[n_] := Times @@ (((fct = FactorInteger[n])[[;; , 1]] - 1)^fct[[;; , 2]]); Select[Range[10^7], CompositeQ[#] && Divisible[# - 1, f[#]] &] (* Amiram Eldar, Dec 31 2020 *)
PROG
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Antti Karttunen, Dec 31 2020
EXTENSIONS
More terms from Amiram Eldar, Dec 31 2020
STATUS
approved