A319370 Composite numbers k such that phi(k)^phi(k) == k + 1 (mod k^2).

91, 18227, 28605, 137481, 538849, 2832797, 3220333, 384792005

Offset: 1

Author

Altug Alkan, Sep 17 2018

Keywords

• nonn
• more

Comments

Composite numbers k such that (k-phi(k))^phi(k) == 1 (mod k^2).

Crossrefs

Cf. A003277, A077816.

Programs

PARI

isok(n) = n>1 && !isprime(n) && Mod(n-eulerphi(n), n^2)^eulerphi(n)==1;