A156893 - OEIS

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A156893

Primes of the form 1+2*product_{i=1..k} (2^i-1).

3, 7, 43, 631, 19531, 1230391, 39846180151, 42638416803867688651, 1430183959005766573513154251 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Primes of the form 2*A005329(k)+1.`
	EXAMPLE	`For n=4, 2(2^1 - 1)(2^2 - 1)(2^3 -1)(2^4 - 1) + 1 = 213715 + 1 = 631`
	CROSSREFS	`Sequence in context: A181729 A162455 A143684 * A050639 A100837 A019011` `Adjacent sequences: A156890 A156891 A156892 * A156894 A156895 A156896`
	KEYWORD	`nonn`
	AUTHOR	`J. M. Bergot (thekingfishb(AT)yahoo.ca), Feb 17 2009`
	EXTENSIONS	`Definition and terms corrected by R. J. Mathar, Jul 10 2011`

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Last modified February 16 08:13 EST 2012. Contains 205893 sequences.