A103042 - OEIS

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A103042

Numbers n such that 6*10^n + 7*R_n - 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

2, 156, 1055, 1997, 8930, 9563, 19560, 26838 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Also numbers n such that (61*10^n-43)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 677...773.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(61*10^n - 43)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A157087 A000725 A151614 * A142006 A124225 A159030` `Adjacent sequences: A103039 A103040 A103041 * A103043 A103044 A103045`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 18 2005`
	EXTENSIONS	`a(7)-a(8) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 14 2010`

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Last modified February 14 10:16 EST 2012. Contains 205614 sequences.