OFFSET
1,6
COMMENTS
a(1) = 1. For n > 1, a(n) is the least positive k such that phi(k*n) >= phi(a(n-1)*(n-1)), where phi(m) is A000010(m).
LINKS
Peter Kagey, Table of n, a(n) for n = 1..10000
MATHEMATICA
a = t = {1}; lim = 72; Do[k = 1; While[EulerPhi[k n] < t[[n - 1]], k++]; AppendTo[a, k]; AppendTo[t, EulerPhi[k n]], {n, 2, lim}]; a (* Michael De Vlieger, Sep 22 2015 *)
PROG
(PARI) lista(nn) = {print1(a=1, ", "); for (n=2, nn, k = 1; phia = eulerphi(a); while(eulerphi(k*n) < phia, k++); a = k*n; print1(k, ", "); ); } \\ Michel Marcus, Oct 05 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Kagey, Sep 03 2015
STATUS
approved