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a(n) = (n - tau(n))*(n - phi(n)), where tau=A000005 and phi=A000010.
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%I #13 Sep 08 2022 08:45:13

%S 0,0,1,2,3,8,5,16,18,36,9,48,11,80,77,88,15,144,17,168,153,216,21,256,

%T 110,308,207,352,27,484,29,416,377,540,341,648,35,680,525,768,39,1020,

%U 41,912,819,1008,45,1216,322,1320,893,1288,51,1656,765,1536,1113,1620

%N a(n) = (n - tau(n))*(n - phi(n)), where tau=A000005 and phi=A000010.

%H Harvey P. Dale, <a href="/A094181/b094181.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A049820(n)*A051953(n).

%t Array[(#-DivisorSigma[0,#])(#-EulerPhi[#])&,60] (* _Harvey P. Dale_, May 18 2012 *)

%o (Magma) [(n-NumberOfDivisors(n))*(n-EulerPhi(n)): n in [1..60]]; // _Vincenzo Librandi_, Aug 31 2018

%Y Cf. A062355.

%K nonn

%O 1,4

%A _Reinhard Zumkeller_, May 06 2004