A103087 - OEIS

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A103087

Numbers n such that 8*10^n + 6*R_n - 3 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 2, 3, 13, 19, 62, 80, 126, 168, 195, 309, 410, 481, 608, 741, 879, 1176, 2688, 6236, 16294, 17317 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (26*10^n-11)/3 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 866...663.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(26*10^n - 11)/3], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A194598 A080359 A193507 * A135118 A084958 A037392` `Adjacent sequences: A103084 A103085 A103086 * A103088 A103089 A103090`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005`
	EXTENSIONS	`a(20)-a(21) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 14 2010`

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Last modified February 14 23:53 EST 2012. Contains 205689 sequences.