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a(n) = sigma(A020492(n)).
2

%I #12 Sep 08 2022 08:45:38

%S 1,3,4,12,28,24,24,72,48,96,120,144,168,192,336,480,360,576,480,720,

%T 720,576,720,1344,1440,1440,1440,1872,1728,1920,1680,2880,2016,1440,

%U 2880,2880,2880,3600,5760,4320,5040,7200,6720,7392,8064,8640,8640,5760,5616

%N a(n) = sigma(A020492(n)).

%H Amiram Eldar, <a href="/A147569/b147569.txt">Table of n, a(n) for n = 1..10000</a> (calculated from the b-file at A020492)

%e a(5) = sigma(A020492(5)) = sigma(12) = 28.

%o (Magma) [ SumOfDivisors(n): n in [1..3500] | SumOfDivisors(n) mod EulerPhi(n) eq 0 ]; // _Klaus Brockhaus_, Nov 09 2008

%o (PARI) {for(n=1, 3500, a=sigma(n); if(a%eulerphi(n)==0, print1(a, ",")))} \\ _Klaus Brockhaus_, Nov 09 2008

%Y Cf. A020492, A023897, A147570.

%K easy,nonn

%O 1,2

%A _Enoch Haga_, Nov 07 2008

%E Edited by _Klaus Brockhaus_, Nov 09 2008