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%I #11 Apr 09 2020 05:24:03
%S 3,5,17,257,413,611,1391,1589,1903,2327,5599,27959,29623,36647,36983,
%T 38863,42851,43919,46463,49513,65537,76759,82969,86567,88759,96839,
%U 111179,116479,129307,171191,184979,213041,277619,301157,310519,346151,362263,372227,375167
%N Numbers that equal to the sum of their iterated absolute Möbius divisor function (A173557).
%C A variant of A082897 (perfect totient numbers) in which the absolute Möbius divisor function (A173557) replaces the Euler totient function (A000010).
%H Amiram Eldar, <a href="/A333873/b333873.txt">Table of n, a(n) for n = 1..350</a> (terms below 4*10^9)
%H Daeyeoul Kim, Umit Sarp, and Sebahattin Ikikardes, <a href="https://doi.org/10.3390/math7111083">Iterating the Sum of Möbius Divisor Function and Euler Totient Function</a>, Mathematics, Vol. 7, No. 11 (2019), pp. 1083-1094.
%e 5 is a term since A173557(5) = 4, A173557(4) = 1, and 4 + 1 = 5.
%t f[p_, e_] := p - 1; u[1] = 1; u[n_] := Times @@ (f @@@ FactorInteger[n]); Select[Range[10^4], Plus @@ FixedPointList[u, #] == 2*# + 1 &]
%Y A019434 is a subsequence.
%Y Cf. A082897, A173557, A286067, A330273, A333871.
%K nonn
%O 1,1
%A _Amiram Eldar_, Apr 08 2020
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