A103089 - OEIS

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A103089

Numbers n such that 8*10^n + 7*R_n - 6 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

5, 6, 185, 401, 480, 1319, 5646, 6029, 16824 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Also numbers n such that (79*10^n-61)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 877...771.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(79*10^n - 61)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A078984 A041257 A041411 * A041601 A041827 A042089` `Adjacent sequences: A103086 A103087 A103088 * A103090 A103091 A103092`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005`
	EXTENSIONS	`1 more term. Next term exceeds 50000. Sean A. Irvine (sairvin(AT)xtra.co.nz), Sep 10 2009`

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Last modified February 15 09:45 EST 2012. Contains 205760 sequences.