A103101 - OEIS

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A103101

Numbers n such that 9*10^n + 5*R_n - 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

2, 20, 104, 329, 1442, 1721, 24887 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Also numbers n such that (86*10^n-23)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 955...553.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(86*10^n - 23)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A086755 A107483 A035599 * A009357 A052361 A001884` `Adjacent sequences: A103098 A103099 A103100 * A103102 A103103 A103104`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005`
	EXTENSIONS	`a(7) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 14 2010`

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Last modified February 16 17:48 EST 2012. Contains 205939 sequences.