A103081 - OEIS

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A103081

Numbers n such that 8*10^n + 4*R_n + 3 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

3, 5, 101, 105, 4097, 5733, 9755 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Also numbers n such that (76*10^n+23)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 844...447.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(76*10^n + 23)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A057663 A056244 A173487 * A003112 A130187 A054266` `Adjacent sequences: A103078 A103079 A103080 * A103082 A103083 A103084`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005`

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Last modified February 15 19:15 EST 2012. Contains 205852 sequences.