A102943 - OEIS

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A102943

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

1, 2, 8, 10, 25, 50, 76, 104, 4406, 8935, 26000 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (16*10^n+11)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 177...779.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(16*10^n + 11)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A122208 A106358 A002510 * A062880 A066707 A107227` `Adjacent sequences: A102940 A102941 A102942 * A102944 A102945 A102946`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 16 2004`
	EXTENSIONS	`Addition of a(11) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 13 2010`

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Last modified February 15 20:03 EST 2012. Contains 205852 sequences.