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A325177 Unitary highly touchable numbers: Numbers m > 1 such that a record number of numbers k have m as the sum of the proper unitary divisors of k. 5

%I #15 Jan 05 2020 05:55:40

%S 2,6,8,12,22,33,49,55,67,79,91,115,121,151,169,175,181,211,295,301,

%T 361,391,421,481,511,571,631,781,841,991,1051,1171,1231,1261,1321,

%U 1471,1561,1681,1891,2101,2311,2731,3151,3361,3571,3991,4201,4291,4411,4621,5251

%N Unitary highly touchable numbers: Numbers m > 1 such that a record number of numbers k have m as the sum of the proper unitary divisors of k.

%C The unitary version of A238895.

%H Amiram Eldar, <a href="/A325177/b325177.txt">Table of n, a(n) for n = 1..78</a>

%H Amiram Eldar, <a href="/A325177/a325177.txt">Table of n, a(n), A324938(a(n)) for n = 1..78</a>

%t us[1] = 0; us[n_] := Times @@ (1 + Power @@@ FactorInteger[n]) - n; m = 300; v = Table[0, {m}]; Do[u = us[k]; If[2 <= u <= m, v[[u]]++], {k, 1, m^2}]; s = {}; vm = -1; Do[If[v[[k]] > vm, vm = v[[k]]; AppendTo[s, k]], {k, 2, m}]; s

%Y Cf. A034448, A034460, A063948, A238895, A324938.

%K nonn

%O 1,1

%A _Amiram Eldar_, Sep 05 2019

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Last modified September 5 05:06 EDT 2024. Contains 375686 sequences. (Running on oeis4.)