id:A068306 - OEIS Search Results

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Numbers n such that n*tau(n)<sigma(n)*bigomega(n) where tau(n)=A000005(n) sigma(n)=A000203(n) and bigomega(n)=A001222(n).

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4, 8, 12, 16, 18, 20, 24, 27, 32, 36, 40, 48, 54, 56, 64, 72, 80, 81, 88, 96, 104, 108, 112, 128, 14, 4, 160, 162, 176, 192, 208, 216, 224, 243, 256, 272, 288, 304, 320, 324, 352, 368, 384, 416, 43, 2, 448, 464, 486, 512, 544, 576, 608, 640, 704, 729, 736, 768, 832 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`In this sequence are numbers of the form p^u u>=p p prime, numbers of the form 2^kp p odd prime and k>=k(p) where k(p)=floor(log(p)/log(2)). Example : the first number of the form 2^k67 in the sequence is 2^667=4288 because floor(log(67)/log(2))=6` `If n=p^(p-1) p prime ntau(n)-sigma(n)*bigomega(n)=1`
	CROSSREFS	`Sequence in context: A020647 A130702 A053806 this_sequence A113645 A086133 A100716` `Adjacent sequences: A068303 A068304 A068305 this_sequence A068307 A068308 A068309`
	KEYWORD	`nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 24 2002`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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