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A322874 Ordinal transform of A007431, which is Möbius transform of Euler phi. 3
1, 1, 2, 3, 1, 2, 1, 1, 1, 3, 1, 4, 1, 4, 2, 2, 1, 5, 1, 3, 2, 6, 1, 2, 1, 7, 1, 3, 1, 8, 1, 1, 2, 9, 2, 3, 1, 10, 2, 1, 1, 11, 1, 3, 2, 12, 1, 4, 1, 13, 3, 3, 1, 14, 2, 1, 2, 15, 1, 4, 1, 16, 1, 2, 1, 17, 1, 4, 2, 18, 1, 2, 1, 19, 3, 3, 2, 20, 1, 3, 2, 21, 1, 4, 3, 22, 3, 1, 1, 23, 1, 3, 2, 24, 2, 3, 1, 25, 3, 4, 1, 26, 1, 1, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
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
Sequence in context: A251046 A064529 A338263 * A091654 A127246 A106038
KEYWORD
nonn
AUTHOR
Antti Karttunen, Dec 29 2018
STATUS
approved

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Last modified March 2 12:34 EST 2024. Contains 370467 sequences. (Running on oeis4.)