A102941 - OEIS

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A102941

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

1, 3, 5, 7, 11, 12, 28, 36, 384, 629, 720, 1398, 2002, 2622, 6457, 19305 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (5*10^n+7)/3 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 166...669.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(5*10^n + 7)/3], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A066168 A109908 A152212 * A114235 A086527 A161554` `Adjacent sequences: A102938 A102939 A102940 * A102942 A102943 A102944`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 16 2004`
	EXTENSIONS	`Addition of a(16) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 12 2010`

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Last modified February 17 20:50 EST 2012. Contains 206085 sequences.