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 A074873 Friendly numbers (see A074902) such that sigma(n) is not friendly. 0
 66, 210, 282, 364, 510, 642, 930, 966, 1080, 1092, 1146, 1624, 2130, 2226, 2346, 2586, 2676, 3560, 3810, 4278, 4872, 7965 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS I do not know how rigorously these numbers have been established. It is possible there are missing terms - see A074902. - N. J. A. Sloane, Sep 15 2002 From Walter Nissen, May 28 2011: (Start) Yes; in particular, if perchance 10 should turn out to have a friend, then 10 would be a(0). Also 30 and 40 might possibly be in this sequence. Numbers without friends are called solitary. (End) LINKS EXAMPLE 6 is friendly, but so is sigma(6)=12, so 6 is not in the sequence. 210 is friendly (with 17360 for example), but sigma(210)=576 is not friendly. CROSSREFS Sequence in context: A255102 A202647 A202640 * A205817 A046393 A268582 Adjacent sequences:  A074870 A074871 A074872 * A074874 A074875 A074876 KEYWORD nonn AUTHOR Jon Perry, Sep 12 2002 STATUS approved

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Last modified May 25 14:51 EDT 2022. Contains 354071 sequences. (Running on oeis4.)