A124579 - OEIS

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A124579

Number of natural numbers less than n which have identical Moebius mu values.

0, 0, 1, 0, 2, 1, 3, 1, 2, 2, 4, 3, 5, 3, 4, 4, 6, 5, 7, 6, 5, 6, 8, 7, 8, 7, 9, 10, 9, 10, 11, 11, 8, 9, 10, 12, 12, 11, 12, 13, 13, 14, 15, 14, 15, 13, 16, 16, 17, 18, 14, 19, 17, 20, 15, 21, 16, 17, 18, 22, 19, 18, 23, 24, 19, 20, 21, 25, 20, 22, 23, 26, 24, 21, 27, 28, 22, 25, 26, 29

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OFFSET

1,5

LINKS

Table of n, a(n) for n=1..80.

EXAMPLE

a(10) = 2 because in the first nine integers less than 10, mu(1) = mu(6) = mu(10).

MATHEMATICA

a[n_] := a[n] = MoebiusMu@n; f[n_] := Count[a /@ Range[n - 1], a@n]; Array[f, 80]

With[{mu=MoebiusMu[Range[80]]}, Table[Count[Take[mu, n], _?(#==MoebiusMu[ n+1]&)], {n, 0, Length[mu]}]] (* Harvey P. Dale, Aug 18 2016 *)

CROSSREFS

Cf. A124580.