id:A103084 - OEIS Search Results

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Numbers n such that 8*10^n + 5*R_n - 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

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1, 2, 7, 44, 56, 338, 1211, 2693, 3536, 3917, 3974, 4046, 6961 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`Also numbers n such that (77*10^n-23)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 855...553.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(77*10^n - 23)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A121418 A014501 A011835 this_sequence A041507 A158107 A145073` `Adjacent sequences: A103081 A103082 A103083 this_sequence A103085 A103086 A103087`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005`

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Last modified November 24 19:42 EST 2009. Contains 167435 sequences.