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A333873 Numbers that equal to the sum of their iterated absolute Möbius divisor function (A173557). 1
3, 5, 17, 257, 413, 611, 1391, 1589, 1903, 2327, 5599, 27959, 29623, 36647, 36983, 38863, 42851, 43919, 46463, 49513, 65537, 76759, 82969, 86567, 88759, 96839, 111179, 116479, 129307, 171191, 184979, 213041, 277619, 301157, 310519, 346151, 362263, 372227, 375167 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
A variant of A082897 (perfect totient numbers) in which the absolute Möbius divisor function (A173557) replaces the Euler totient function (A000010).
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..350 (terms below 4*10^9)
Daeyeoul Kim, Umit Sarp, and Sebahattin Ikikardes, Iterating the Sum of Möbius Divisor Function and Euler Totient Function, Mathematics, Vol. 7, No. 11 (2019), pp. 1083-1094.
EXAMPLE
5 is a term since A173557(5) = 4, A173557(4) = 1, and 4 + 1 = 5.
MATHEMATICA
f[p_, e_] := p - 1; u[1] = 1; u[n_] := Times @@ (f @@@ FactorInteger[n]); Select[Range[10^4], Plus @@ FixedPointList[u, #] == 2*# + 1 &]
CROSSREFS
A019434 is a subsequence.
Sequence in context: A278138 A273870 A272060 * A058910 A307843 A023394
KEYWORD
nonn
AUTHOR
Amiram Eldar, Apr 08 2020
STATUS
approved

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Last modified June 16 12:15 EDT 2024. Contains 373429 sequences. (Running on oeis4.)