A103052 - OEIS

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A103052

Numbers n such that 7*10^n + 2*R_n - 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 4, 16, 25, 29, 41, 47, 88, 1132, 1570, 3985, 10609, 12175, 29369 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (65*10^n-11)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 722...221.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(65*10^n - 11)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A174999 A160996 A173926 * A202303 A087055 A135556` `Adjacent sequences: A103049 A103050 A103051 * A103053 A103054 A103055`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005`
	EXTENSIONS	`a(12)-a(14) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 14 2010`

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Last modified February 15 08:20 EST 2012. Contains 205729 sequences.