A102999 - OEIS

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A102999

Numbers n such that 4*10^n + 8*R_n - 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 2, 7, 14, 25, 116, 427, 595, 637, 776, 1706, 16628 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (44*10^n-17)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 488...887.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(44*10^n - 17)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A119354 A088207 A194111 * A014112 A068040 A200084` `Adjacent sequences: A102996 A102997 A102998 * A103000 A103001 A103002`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 17 2005`
	EXTENSIONS	`Addition of a(12) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 13 2010`

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