id:A134666 - OEIS Search Results

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Number of multiply perfect numbers (A007691) having 2^n as the highest power of 2.

+0
2

1, 1, 2, 2, 1, 4, 1, 5, 4, 4, 3, 6, 1, 3, 4, 5, 1, 9, 1, 19, 8, 9, 3, 5, 6, 7, 16, 13, 26, 20, 1, 6, 8, 6, 13, 23, 20, 6, 9, 33, 10, 11, 14, 18, 15, 13, 32, 23, 23, 18, 12, 20, 26, 21, 16, 17, 7, 11, 20, 15, 1, 10, 17, 14, 13, 26, 21, 16, 24, 13, 21, 27, 18, 14, 16, 21, 38, 19, 12, 26, 13, 23 (list; graph; listen)

	OFFSET	`0,3`
	COMMENT	`It appears that a(n)>0 for all n. With the exception of n=2, a(n)=1 when n is p-1, where p is a Mersenne prime (A000043). Flammenkamp has an attactive graph of this sequence, including n for which there is incomplete data.`
	LINKS	`Achim Flammenkamp, The Multiply Perfect Numbers Page`
	EXAMPLE	`a(2)=2 because only 28 and 2178540 have 2^2 as their highest power of 2.`
	CROSSREFS	`Cf. A134665 (highest power of 2 for each MPN).` `Sequence in context: A054995 A018219 A116633 this_sequence A129712 A051720 A022693` `Adjacent sequences: A134663 A134664 A134665 this_sequence A134667 A134668 A134669`
	KEYWORD	`nonn`
	AUTHOR	`T. D. Noe (noe(AT)sspectra.com), Nov 05 2007`

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Last modified December 10 00:48 EST 2009. Contains 170565 sequences.

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