A103083 - OEIS

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A103083

Numbers n such that 8*10^n + 5*R_n - 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

21, 27, 60, 471, 1074, 5781 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Also numbers n such that (77*10^n-41)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 855...551.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(77*10^n - 41)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A098898 A098768 A114168 * A120735 A009727 A168105` `Adjacent sequences: A103080 A103081 A103082 * A103084 A103085 A103086`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005`

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Last modified February 17 19:13 EST 2012. Contains 206085 sequences.