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A327945 Nonunitary pseudoperfect numbers: numbers that are equal to the sum of a subset of their nonunitary divisors. 5

%I #11 Jul 13 2021 19:43:34

%S 24,36,48,72,80,96,108,112,120,144,160,168,180,192,200,216,224,240,

%T 252,264,288,300,312,320,324,336,352,360,384,392,396,400,408,416,432,

%U 448,456,468,480,504,528,540,552,560,576,588,600,612,624,640,648,672,684

%N Nonunitary pseudoperfect numbers: numbers that are equal to the sum of a subset of their nonunitary divisors.

%C The nonunitary version of A005835.

%H Amiram Eldar, <a href="/A327945/b327945.txt">Table of n, a(n) for n = 1..10000</a>

%e 36 is in the sequence since its nonunitary divisors are 2, 3, 6, 12, 18 and 36 = 6 + 12 + 18.

%t nudiv[n_] := Module[{d = Divisors[n]}, Select[d, GCD[#, n/#] > 1 &]]; s = {}; Do[d = nudiv[n]; If[Total[d] < n, Continue[]]; c = SeriesCoefficient[Series[Product[1 + x^d[[i]], {i, Length[d]}], {x, 0, n}], n]; If[c > 0, AppendTo[s, n]], {n, 1, 700}]; s

%Y Supersequence of A064591.

%Y Cf. A005835, A064597, A293188, A292985, A306983.

%K nonn

%O 1,1

%A _Amiram Eldar_, Sep 30 2019

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Last modified August 14 10:47 EDT 2024. Contains 375159 sequences. (Running on oeis4.)