A103109 - OEIS

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A103109

Numbers n such that 9*10^n + 8*R_n - 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 3, 4, 6, 9, 12, 16, 34, 129, 243, 252, 529, 4885, 6363, 12951, 13188, 29931, 34888 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (89*10^n-17)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 988...887.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(89*10^n - 17)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A191287 A202171 A097922 * A078743 A096846 A140570` `Adjacent sequences: A103106 A103107 A103108 * A103110 A103111 A103112`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005`
	EXTENSIONS	`a(15)-a(18) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 14 2010`

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Last modified February 16 10:53 EST 2012. Contains 205904 sequences.