id:A115909 - OEIS Search Results

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Numbers n such that sigma(n) times n is a triangular number.

+0
3

1, 2, 4, 8, 16, 32, 57, 64, 65, 85, 87, 128, 256, 512, 1024, 1245, 1421, 2048, 3146, 3330, 3790, 4096, 6695, 7257, 8192, 10137, 16384, 25884, 32768, 34420, 34551, 34947, 65536, 131072, 208495, 262144, 348161, 440495, 524288, 530270, 534430 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`Infinite, since all the powers of 2 belong to the sequence.`
	EXAMPLE	`sigma(1421)*1421=2429910=T(2204).`
	CROSSREFS	`Cf. A115904, A115910.` `Sequence in context: A007055 A072207 A033860 this_sequence A056644 A007813 A005309` `Adjacent sequences: A115906 A115907 A115908 this_sequence A115910 A115911 A115912`
	KEYWORD	`nonn`
	AUTHOR	`Giovanni Resta (g.resta(AT)iit.cnr.it), Feb 06 2006`

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Last modified November 18 20:14 EST 2008. Contains 147244 sequences.

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