A103056 - OEIS

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A103056

Numbers n such that 7*10^n + 3*R_n + 6 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 2, 5, 7, 85, 345, 1595, 2105, 6386, 9119, 9332, 14707 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (22*10^n+17)/3 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 733...339.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(22*10^n + 17)/3], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A182785 A041125 A042257 * A041445 A041961 A058854` `Adjacent sequences: A103053 A103054 A103055 * A103057 A103058 A103059`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005`
	EXTENSIONS	`a(12) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 14 2010`

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Last modified February 16 17:48 EST 2012. Contains 205939 sequences.