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

Offset: 1

Author

Benoit Cloitre, May 01 2002

Keywords

• easy
• nonn

Links

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

Programs

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 *)

PARI

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