A103011 - OEIS

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A103011

Numbers n such that 5*10^n + 2*R_n + 7 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 5, 11, 14, 62, 74, 107, 110, 121, 128, 139, 320, 2956, 11116 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (47*10^n+61)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 522...229.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(46*10^n + 61)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A102801 A196206 A079030 * A137002 A091718 A078002` `Adjacent sequences: A103008 A103009 A103010 * A103012 A103013 A103014`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 18 2005`
	EXTENSIONS	`Addition of a(14) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 12 2010`

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Last modified February 15 16:56 EST 2012. Contains 205825 sequences.