OFFSET
1,1
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..11
EXAMPLE
The perfect number 28 is in the sequence because 28 = sigma(12).
sigma(727145809044307968) = sigma(1152771972099211264) = 2305843008139952128.
PROG
(Magma) Set(Sort([&+Divisors(m): m in [1..10^7] | &+Divisors(&+Divisors(m)) eq 2 * &+Divisors(m)]))
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, May 16 2022
EXTENSIONS
a(8)-a(10) from Amiram Eldar, May 12 2024
STATUS
approved