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

%S 1,1,2,2,4,6,8,8,24,12,24,24,24,48,48,48,72,48,120,80,72,192,180,96,

%T 144,180,240,144,192,240,336,192,288,720,480,360,720,720,480,720,720,

%U 720,672,672,576,720,960,1440,1872,1680,960,1120,1848,2016,1440,1728,1440

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

%H Amiram Eldar, <a href="/A147570/b147570.txt">Table of n, a(n) for n = 1..10000</a> (calculated from the b-file at A020492)

%e a(5) = phi(A020492(5)) = phi(12) = 4.

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

%o (PARI) {for(n=1, 5000, a=eulerphi(n); if(sigma(n)%a==0, print1(a, ",")))} \\ _Klaus Brockhaus_, Nov 09 2008

%Y Cf. A000010 (Euler totient function phi(n)), A000203 (sigma(n), sum of divisors of n), A020492 (balanced numbers, numbers n such that phi(n) divides sigma(n)), A023897 (sigma(n) / phi(n) for balanced numbers), A147569.

%K easy,nonn

%O 1,3

%A _Enoch Haga_, Nov 07 2008

%E Edited by _Klaus Brockhaus_, Nov 09 2008