A069797 - OEIS

A069797

Smallest k>n such that phi(n) divides phi(k).

2, 3, 4, 5, 8, 7, 9, 10, 13, 12, 22, 13, 21, 18, 16, 17, 32, 19, 27, 24, 26, 25, 46, 30, 33, 28, 37, 35, 58, 32, 61, 34, 41, 40, 39, 37, 57, 54, 45, 48, 55, 45, 49, 50, 52, 67, 94, 51, 86, 55, 64, 56, 106, 57, 75, 65, 63, 87, 118, 64, 77, 77, 73, 68, 97, 75, 134, 80, 89, 72

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OFFSET

1,1

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..10000

MATHEMATICA

sk[n_]:=Module[{p1=EulerPhi[n], k=n+1}, While[Mod[EulerPhi[k], p1]!=0, k++]; k]; Array[sk, 70] (* Harvey P. Dale, Jun 14 2022 *)

PROG

(PARI) for(s=1, 80, n=s+1; while(frac(eulerphi(n)/eulerphi(s))>0, n++); print1(n, ", "); )

CROSSREFS

Sequence in context: A352047 A245822 A357260 * A158979 A233249 A330573

Adjacent sequences: A069794 A069795 A069796 * A069798 A069799 A069800

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, May 01 2002

STATUS

approved