A099417 - OEIS

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A099417

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

0, 1, 3, 4, 6, 10, 15, 22, 88, 207, 528, 960, 2100 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,3`
	COMMENTS	`Also numbers n such that (5*10^n+13)/9 is prime.`
	LINKS	`Index entries for primes involving repunits`
	MATHEMATICA	`Do[ If[ PrimeQ[ 5(10^n - 1)/9 + 2], Print[n]], {n, 0, 5000}]`
	CROSSREFS	`Sequence in context: A125869 A059618 A114736 * A139463 A068922 A032408` `Adjacent sequences: A099414 A099415 A099416 * A099418 A099419 A099420`
	KEYWORD	`nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 14 2004`

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Last modified February 16 17:46 EST 2012. Contains 205938 sequences.