A102997 - OEIS

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A102997

Numbers n such that 4*10^n + 8*R_n - 7 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

1, 463 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (44*10^n-71)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 488...881.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(44*10^n - 71)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A140905 A025038 A028684 * A139662 A140030 A020371` `Adjacent sequences: A102994 A102995 A102996 * A102998 A102999 A103000`
	KEYWORD	`bref,more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 17 2005`

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Last modified February 15 15:20 EST 2012. Contains 205823 sequences.