OFFSET
1,2
COMMENTS
A083874 is a subset of this sequence: it lists the fixed points of the transform n -> sigma(n)+tau(n)-n.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..900 (terms 1..50 from Paolo P. Lava)
EXAMPLE
Fixed points: 1, 3, 14, 52, 130, 184, 656, 8648, 12008, 34688, ...
sigma(144) = 403, tau(144) = 15 and 403 + 15 - 144 = 274.
sigma(274) = 414, tau(274) = 4 and 414 + 4 - 274 = 144.
MAPLE
with(numtheory); P:=proc(q)local a, n;
for n from 1 to q do a:=sigma(n)+tau(n)-n;
if sigma(a)+tau(a)-a=n then print(n);
fi; od; end: P(10^6);
MATHEMATICA
f[n_] := DivisorSigma[0, n] + DivisorSigma[1, n] - n; s={}; Do[m = f[n]; If[f[m] == n, AppendTo[s, n]], {n, 1, 500000}]; s (* Amiram Eldar, Jul 12 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Paolo P. Lava, Feb 20 2014
STATUS
approved