OFFSET
1,2
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
{1}~Join~Select[Range@ 180, (GCD @@ (Divisors[#] - 1)) CarmichaelLambda@ # == EulerPhi@ # &] (* Michael De Vlieger, Jan 10 2017 *)
PROG
(PARI) a258409(n) = if(n%2==0, return(1)); if(n%3==0, return(2)); if(n%5==0 && n%4 != 1, return(2)); gcd(apply(p->p-1, factor(n)[, 1]));
a002322(n) = lcm(znstar(n)[2]);
is(n) = a258409(n) * a002322(n) == eulerphi(n);
CROSSREFS
KEYWORD
nonn
AUTHOR
Thomas Ordowski and Altug Alkan, Jan 09 2017
STATUS
approved