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

24, 36, 48, 72, 80, 96, 108, 112, 120, 144, 160, 168, 180, 192, 200, 216, 224, 240, 252, 264, 288, 300, 312, 320, 324, 336, 352, 360, 384, 392, 396, 400, 408, 416, 432, 448, 456, 468, 480, 504, 528, 540, 552, 560, 576, 588, 600, 612, 624, 640, 648, 672, 684

Offset: 1

Author

Amiram Eldar, Sep 30 2019

Keywords

• nonn

Comments

The nonunitary version of A005835.

Examples

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

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Supersequence of A064591.

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

Programs

Mathematica

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