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A007423 mu(n) + 1, where mu is the Moebius function.
(Formerly M0011)

%I M0011

%S 2,0,0,1,0,2,0,1,1,2,0,1,0,2,2,1,0,1,0,1,2,2,0,1,1,2,1,1,0,0,0,1,2,2,

%T 2,1,0,2,2,1,0,0,0,1,1,2,0,1,1,1,2,1,0,1,2,1,2,2,0,1,0,2,1,1,2,0,0,1,

%U 2,0,0,1,0,2,1,1,2,0,0,1,1,2,0,1,2,2,2,1,0,1,2,1,2,2,2,1,0,1,1,1

%N mu(n) + 1, where mu is the Moebius function.

%D G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers. 3rd ed., Oxford Univ. Press, 1954, p. 234.

%D K. Ireland and M. Rosen, A Classical Introduction to Modern Number Theory. Springer-Verlag, NY, 1982, p. 19.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Reinhard Zumkeller, <a href="/A007423/b007423.txt">Table of n, a(n) for n = 1..10000</a>

%p with(numtheory); A007423:=n->mobius(n)+1; seq(A007423(k), k=1..100); # _Wesley Ivan Hurt_, Oct 24 2013

%t MoebiusMu[Range[100]]+1 (* _Harvey P. Dale_, Nov 08 2011 *)

%o (Haskell)

%o a007423 = (+ 1) . a008683 -- _Reinhard Zumkeller_, Jul 30 2014

%o (PARI) a(n)=moebius(n)+1 \\ _Charles R Greathouse IV_, Feb 25 2018

%Y Cf. A008683.

%Y a(n) = abs(A007423(n))

%K easy,nonn,nice

%O 1,1

%A _N. J. A. Sloane_.

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Last modified December 9 22:27 EST 2019. Contains 329880 sequences. (Running on oeis4.)