|
|
A147569
|
|
a(n) = sigma(A020492(n)).
|
|
2
|
|
|
1, 3, 4, 12, 28, 24, 24, 72, 48, 96, 120, 144, 168, 192, 336, 480, 360, 576, 480, 720, 720, 576, 720, 1344, 1440, 1440, 1440, 1872, 1728, 1920, 1680, 2880, 2016, 1440, 2880, 2880, 2880, 3600, 5760, 4320, 5040, 7200, 6720, 7392, 8064, 8640, 8640, 5760, 5616
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
EXAMPLE
|
a(5) = sigma(A020492(5)) = sigma(12) = 28.
|
|
PROG
|
(Magma) [ SumOfDivisors(n): n in [1..3500] | SumOfDivisors(n) mod EulerPhi(n) eq 0 ]; // Klaus Brockhaus, Nov 09 2008
(PARI) {for(n=1, 3500, a=sigma(n); if(a%eulerphi(n)==0, print1(a, ", ")))} \\ Klaus Brockhaus, Nov 09 2008
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|