A015874 Numbers k such that phi(k + 10) | (sigma(k) + 10).

5, 40, 108, 9544

Offset

1,1

Comments

The next term, if it exists, is greater than 10^8. - Charles R Greathouse IV, Sep 25 2012

a(5) > 10^10, if it exists. - Amiram Eldar, Dec 09 2023

Links

Table of n, a(n) for n=1..4.

Mathematica

Select[Range[10000], Divisible[DivisorSigma[1, #]+10, EulerPhi[#+10]]&] (* Harvey P. Dale, Jul 10 2021 *)

Prog

(PARI) is(n)=!((sigma(n)+10)%eulerphi(n+10)) \\ Charles R Greathouse IV, Sep 25 2012

Crossrefs

Cf. A000010, A000203.

Sequence in context: A222366 A029538 A153795 * A244725 A319098 A209346

Adjacent sequences: A015871 A015872 A015873 * A015875 A015876 A015877

Keyword

nonn,more

Author

Robert G. Wilson v

Status

approved