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A144922 Numbers n such that n*sigma_2(n)/sigma_1(n) is an integer +0
1
1, 4, 6, 9, 12, 16, 18, 20, 24, 25, 28, 36, 44, 45, 48, 49, 50, 54, 60, 64, 72, 81, 90, 92, 96, 100, 108, 112, 117, 121, 132, 140, 144, 150, 153, 162, 168, 169, 180, 192, 196 (list; graph; listen)
OFFSET

1,2

COMMENT

n*A001157(n)/A000203(n) is an integer. This sequence is connected closely with Ore divisor numbers (A001599) and RMS numbers (A140480).

CROSSREFS

Cf. A000203, A001157, A001599, A140480

Sequence in context: A024675 A163656 A100915 this_sequence A088765 A078782 A165897

Adjacent sequences: A144919 A144920 A144921 this_sequence A144923 A144924 A144925

KEYWORD

easy,nonn

AUTHOR

Ctibor O. Zizka (c.zizka(AT)email.cz), Sep 25 2008

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.


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