A102977 - OEIS

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A102977

Numbers n such that 3*10^n + 7*R_n + 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

0, 2, 3, 5, 6, 20, 776, 1185, 3164, 4212, 10733, 21726 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (34*10^n+11)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 377...779.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(34*10^n + 11)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A126250 A109628 A192367 * A131599 A076384 A124648` `Adjacent sequences: A102974 A102975 A102976 * A102978 A102979 A102980`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 17 2004`
	EXTENSIONS	`Addition of a(11)-a(12) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 13 2010`

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Last modified February 15 12:18 EST 2012. Contains 205785 sequences.