A103028 - OEIS

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A103028

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

1, 2, 32, 43, 973, 1195, 4471, 5684, 7988 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (55*10^n+53)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 611...117.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(55*10^n + 53)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A022378 A193419 A160557 * A139732 A037313 A122127` `Adjacent sequences: A103025 A103026 A103027 * A103029 A103030 A103031`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 18 2005`

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Last modified February 17 17:35 EST 2012. Contains 206061 sequences.