OFFSET
1,1
EXAMPLE
a(3) = 88092 is a term because sigma(88092) = 222768, sigma(222768) = 812448 and sigma(88092 + 222768) = sigma(310860) = 1035216 = 222768 + 812448.
MAPLE
filter:= proc(k) uses numtheory; local s;
s:= sigma(k);
sigma(k+s) = s + sigma(s)
end proc:
select(filter, [$1..10^7]);
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Israel, Oct 05 2024
STATUS
approved