A139307 - OEIS

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A139307

(2^(2p - 1)) - 1, where p is A000043(n).

7, 31, 511, 8191, 33554431, 8589934591, 137438953471, 2305843009213693951, 2658455991569831745807614120560689151, 191561942608236107294793378393788647952342390272950271 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Ultraperfect numbers (A139306) minus 1.`
	FORMULA	`a(n) = (2^(2*A000043(n) - 1)) - 1 = A139306(n) - 1.`
	EXAMPLE	`a(5)=33554431 because A000043(5)=13 and (2^(2*13 - 1))-1 = 2^25 - 1 = 33554431.`
	CROSSREFS	`Cf. A139287, A139295, A139306.` `Sequence in context: A153028 A135630 A139287 * A197451 A197301 A191297` `Adjacent sequences: A139304 A139305 A139306 * A139308 A139309 A139310`
	KEYWORD	`nonn`
	AUTHOR	`Omar E. Pol (info(AT)polprimos.com), Apr 13 2008, May 08 2008`

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Last modified February 17 21:13 EST 2012. Contains 206085 sequences.