OFFSET
1,3
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
MATHEMATICA
A007431[n_] := Sum[EulerPhi[d] MoebiusMu[n/d], {d, Divisors[n]}];
b[_] = 0;
a[n_] := a[n] = With[{t = A007431[n]}, b[t] = b[t]+1];
Array[a, 105] (* Jean-François Alcover, Dec 20 2021 *)
PROG
(PARI)
up_to = 65537;
ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om, invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om, invec[i], (1+pt))); outvec; };
A007431(n) = sumdiv(n, d, moebius(n/d)*eulerphi(d));
v322874 = ordinal_transform(vector(up_to, n, A007431(n)));
A322874(n) = v322874[n];
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Dec 29 2018
STATUS
approved