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

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

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..8.

Prog

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

Crossrefs

Cf. A003277, A077816.

Sequence in context: A370780 A168624 A131442 * A116507 A083828 A348088

Adjacent sequences: A319367 A319368 A319369 * A319371 A319372 A319373

Keyword

nonn,more

Author

Altug Alkan, Sep 17 2018

Status

approved