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Denominator of product{k=1 to n} k^mu(k), where mu is the Moebius function A008683.
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%I #29 Feb 28 2022 12:09:36

%S 1,2,6,6,30,5,35,35,35,7,77,77,1001,143,143,143,2431,2431,46189,46189,

%T 46189,4199,96577,96577,96577,7429,7429,7429,215441,215441,6678671,

%U 6678671,6678671,392863,392863,392863,14535931,765049,765049,765049

%N Denominator of product{k=1 to n} k^mu(k), where mu is the Moebius function A008683.

%C a(n) is also the denominator of H(n)^2 * n! for all n < 897, where H(n) = 1 + 1/2 + ... + 1/n is the n-th harmonic number. - _John M. Campbell_, May 13 2011

%H Ivan Neretin and Michael De Vlieger, <a href="/A130087/b130087.txt">Table of n, a(n) for n = 1..4642</a> (first 1000 terms from Ivan Neretin)

%p with(numtheory): a:=n->denom(product(k^mobius(k),k=1..n)): seq(a(n),n=1..50); # _Emeric Deutsch_, May 11 2007

%t Table[Denominator[HarmonicNumber[n]^2*(n!)],{n, 200}]

%t (* Second program: *)

%t With[{s = Array[#^MoebiusMu@ # &, 39]}, Denominator@ Table[Times @@ Take[s, n], {n, Length@ s}]] (* _Michael De Vlieger_, Sep 20 2017 *)

%o (PARI) a(n)=denominator(prod(k=1,n,k^moebius(k))) \\ _Charles R Greathouse IV_, Mar 10 2012

%Y Cf. A130086, A130088, A130089.

%K frac,nonn

%O 1,2

%A _Leroy Quet_, May 06 2007

%E More terms from _Emeric Deutsch_, May 11 2007