A353801 - OEIS

%I #12 May 13 2022 18:24:37

%S 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,2,1,

%T 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,4,1,1,1,

%U 2,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,3,1,2,1,1,1,1,1,1,1,1,1,1,1,2

%N a(n) = A049559(n) / A187730(n), where A049559(n) and A187730(n) are the greatest common divisors between Euler phi(n) and n-1, and between Carmichael lambda(n) and n-1, respectively.

%H Antti Karttunen, <a href="/A353801/b353801.txt">Table of n, a(n) for n = 1..100000</a>

%t a[n_] := GCD[n - 1, EulerPhi[n]] / GCD[n - 1, CarmichaelLambda[n]]; Array[a, 100] (* _Amiram Eldar_, May 13 2022 *)

%o (PARI)

%o A049559(n) = gcd(n-1, eulerphi(n));

%o A187730(n) = gcd(lcm(znstar(n)[2]), n-1); \\ From A187730

%o A353801(n) = (A049559(n) / A187730(n));

%Y Cf. A280262 (positions of terms > 1).

%Y Cf. A000010, A002322, A049559, A187730, A353483, A353808.

%Y Cf. also A034380.

%K nonn

%O 1,21

%A _Antti Karttunen_, May 13 2022