A102994 - OEIS

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A102994

Numbers n such that 4*10^n + 6*R_n - 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 2, 7, 9, 14, 24, 45, 49, 73, 74, 232, 338, 397, 504, 1063, 2817, 5305, 16768, 27060 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (14*10^n-17)/3 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 466...661.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(14*10^n - 17)/3], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A184400 A074244 A190565 * A168132 A085544 A154789` `Adjacent sequences: A102991 A102992 A102993 * A102995 A102996 A102997`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 17 2005`
	EXTENSIONS	`Addition of a(18)-a(19) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 10 2010`

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Last modified February 16 14:37 EST 2012. Contains 205930 sequences.