OFFSET
1,2
COMMENTS
After the first term a(1) = 1, the next odd term is a(5) = 105, the next term that is coprime to 6 is a(133) = 6545, and the next term that is coprime to 30 is a(322) = 19019.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Range[2000], # == 1 || Divisible[LCM @@ (Rest @ Divisors[#] - 1), #] &]
PROG
(PARI) is(k) = !(lcm(apply(x -> if(x > 1, x-1, x), divisors(k))) % k);
CROSSREFS
KEYWORD
nonn,easy,new
AUTHOR
Amiram Eldar, Nov 12 2024
STATUS
approved