A103022 - OEIS

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A103022

Numbers n such that 5*10^n + 8*R_n - 7 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

3, 5, 6, 21, 309, 816, 858, 1115, 1419, 1689, 12009, 18693, 28098 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Also numbers n such that (53*10^n-71)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 588...881.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(53*10^n - 71)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A192119 A050563 A168156 * A086189 A137082 A099414` `Adjacent sequences: A103019 A103020 A103021 * A103023 A103024 A103025`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 18 2005`
	EXTENSIONS	`Addition of a(11)-a(13) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 13 2010`

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Last modified February 15 05:45 EST 2012. Contains 205694 sequences.