A103023 - OEIS

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A103023

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

2, 6, 8, 20, 108, 288, 306, 462, 20102 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Also numbers n such that (53*10^n-17)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 588...887.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(53*10^n - 17)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A134136 A185165 A058775 * A111247 A045656 A129342` `Adjacent sequences: A103020 A103021 A103022 * A103024 A103025 A103026`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 18 2005`
	EXTENSIONS	`Addition of a(9) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 13 2010`

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Last modified February 14 16:54 EST 2012. Contains 205635 sequences.