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A076359 a(n) = denominator(n!/phi(n!)).

%I A076359 #20 Oct 18 2018 20:53:54
%S A076359 1,1,1,1,4,4,8,8,8,8,16,16,192,192,192,192,3072,3072,55296,55296,
%T A076359 55296,55296,110592,110592,110592,110592,110592,110592,442368,442368,
%U A076359 13271040,13271040,13271040,13271040,13271040,13271040,477757440
%N A076359 a(n) = denominator(n!/phi(n!)).
%C A076359 Numerator of Product_{p<=n, p prime} (1 - 1/p). - _Franz Vrabec_, Jan 28 2014
%H A076359 Robert Israel, <a href="/A076359/b076359.txt">Table of n, a(n) for n = 1..2926</a>
%F A076359 a(n) = denominator(A000142(n)/A048855(n)).
%F A076359 a(n) = A038110(A036234(n)). - _Robert Israel_, Oct 18 2018
%p A076359 P:= 1: p:= 1:  v:= 1:
%p A076359 while p < 100 do q:= nextprime(p);
%p A076359    for i from p to q-1 do A[i]:= v od;
%p A076359    P:= P * (1-1/q);
%p A076359    v:= numer(P);
%p A076359    p:= q;
%p A076359 od:
%p A076359 seq(A[i],i=1..q-1); # _Robert Israel_, Oct 18 2018
%t A076359 dnf[n_]:=With[{nn=n!},Denominator[nn/EulerPhi[nn]]]; Array[dnf,40] (* _Harvey P. Dale_, Feb 21 2015 *)
%o A076359 (PARI) a(n) = numerator(prod(p=1, n, if (isprime(p),(1-1/p), 1))); \\ _Michel Marcus_, Jan 28 2014
%Y A076359 Cf. A000005, A000142, A036234, A038110, A048855, A076358.
%K A076359 easy,nonn,frac
%O A076359 1,5
%A A076359 _Labos Elemer_, Oct 08 2002