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A152615 Numbers n with property that exactly two subsets of proper divisors of n sum to n. 1
12, 18, 42, 56, 66, 100, 176, 196, 208, 348, 372, 444, 460, 492, 516, 550, 564, 580, 636, 708, 732, 736, 738, 774, 804, 812, 820, 846, 852, 868, 876, 928, 948, 954, 968, 992, 996, 1036, 1062, 1068, 1098, 1148, 1164, 1204, 1206, 1212, 1236, 1278, 1284, 1308 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..50.

EXAMPLE

n=12: proper divisors of 12 = {1,2,3,4,6} and 12=2+4+6=1+2+3+6.

MATHEMATICA

spdQ[n_]:=Module[{pds=Most[Divisors[n]]}, Length[Select[Subsets[ pds, Length[ pds]], Total[#] == n&]]==2]; Select[Range[1400], spdQ] (* Harvey P. Dale, Jan 23 2015 *)

CROSSREFS

Cf. A064771, A065205, A065235.

Sequence in context: A197464 A124205 A133403 * A258088 A259263 A279369

Adjacent sequences:  A152612 A152613 A152614 * A152616 A152617 A152618

KEYWORD

nonn

AUTHOR

Zak Seidov, Oct 29 2009

STATUS

approved

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Last modified October 16 21:10 EDT 2019. Contains 328103 sequences. (Running on oeis4.)