A103014 - OEIS

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A103014

Numbers n such that 5*10^n + 4*R_n - 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 3, 4, 9, 12, 60, 268, 289, 384, 795, 3474, 9180 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (49*10^n-13)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 544...443.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(49*10^n - 13)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A034418 A034421 A029448 * A116552 A167930 A124285` `Adjacent sequences: A103011 A103012 A103013 * A103015 A103016 A103017`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 18 2005`

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Last modified February 17 13:18 EST 2012. Contains 206031 sequences.