A102971 - OEIS

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A102971

Numbers n such that 3*10^n + 5*R_n - 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 6, 9, 15, 24, 48, 73, 75, 97, 249, 273, 2488, 14499 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (32*10^n-41)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 355...551.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(32*10^n-41)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A001748 A097426 A075278 * A023885 A031209 A031326` `Adjacent sequences: A102968 A102969 A102970 * A102972 A102973 A102974`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 17 2004`
	EXTENSIONS	`Addition of a(13) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 13 2010`

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Last modified February 14 20:38 EST 2012. Contains 205663 sequences.