OFFSET
1,2
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(9) = 88 is a term because tau(88) = 8, tau(8) = 4 and tau(88 + 8) = tau(96) = 12 = 8 + 4.
MAPLE
filter:= proc(k) uses numtheory; local s;
s:= tau(k);
tau(k+s) = s + tau(s)
end proc:
select(filter, [$1..1000]);
MATHEMATICA
Select[Range[680], DivisorSigma[0, #+DivisorSigma[0, #]]==DivisorSigma[0, #]+DivisorSigma[0, DivisorSigma[0, #]] &] (* Stefano Spezia, Oct 06 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Israel, Oct 06 2024
STATUS
approved