A327979 a(n) = gcd(n, A002322(n)), where A002322 is Carmichael lambda, also known as psi.

1, 1, 1, 2, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 1, 4, 1, 6, 1, 4, 3, 2, 1, 2, 5, 2, 9, 2, 1, 2, 1, 8, 1, 2, 1, 6, 1, 2, 3, 4, 1, 6, 1, 2, 3, 2, 1, 4, 7, 10, 1, 4, 1, 18, 5, 2, 3, 2, 1, 4, 1, 2, 3, 16, 1, 2, 1, 4, 1, 2, 1, 6, 1, 2, 5, 2, 1, 6, 1, 4, 27, 2, 1, 6, 1, 2, 1, 2, 1, 6, 1, 2, 3, 2, 1, 8, 1, 14, 3, 20, 1, 2, 1, 4, 3

Offset: 1

Author

Antti Karttunen, Oct 04 2019

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537

Crossrefs

Cf. A002322.

Cf. also A009191, A009194, A009195, A306695.

Programs

Mathematica

Array[GCD[#, CarmichaelLambda[#]] &, 100] (* Amiram Eldar, Oct 04 2019 *)

PARI

A327979(n) = gcd(n, lcm(znstar(n)[2]));

Formula

a(n) = gcd(n, A002322(n)).