A353801 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.

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, 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, 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

Offset

1,21

Links

Antti Karttunen, Table of n, a(n) for n = 1..100000

Mathematica

a[n_] := GCD[n - 1, EulerPhi[n]] / GCD[n - 1, CarmichaelLambda[n]]; Array[a, 100] (* Amiram Eldar, May 13 2022 *)

Prog

(PARI)
A049559(n) = gcd(n-1, eulerphi(n));
A187730(n) = gcd(lcm(znstar(n)[2]), n-1); \\ From A187730
A353801(n) = (A049559(n) / A187730(n));

Crossrefs

Cf. A280262 (positions of terms > 1).

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

Cf. also A034380.

Sequence in context: A287656 A043286 A172098 * A333254 A204162 A266227

Adjacent sequences: A353798 A353799 A353800 * A353802 A353803 A353804

Keyword

nonn

Author

Antti Karttunen, May 13 2022

Status

approved