A103062 - OEIS

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A103062

Numbers n such that 7*10^n + 5*R_n + 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 3, 237, 243, 351, 967, 1843, 7405, 9633 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (68*10^n+31)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 755...559.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(68*10^n + 31)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A072320 A162603 A053970 * A157723 A142730 A024044` `Adjacent sequences: A103059 A103060 A103061 * A103063 A103064 A103065`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005`

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Last modified February 17 07:41 EST 2012. Contains 205998 sequences.