A099416 - OEIS

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A099416

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

0, 1, 2, 8, 26, 66, 74, 233, 473, 540, 2774 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,3`
	COMMENTS	`Also numbers n such that (5*10^n-23)/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: A102942 A206803 A100504 * A101696 A155861 A136594` `Adjacent sequences: A099413 A099414 A099415 * A099417 A099418 A099419`
	KEYWORD	`nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 14 2004`

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Last modified February 16 23:45 EST 2012. Contains 205978 sequences.