A102958 - OEIS

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A102958

Numbers n such that 2*10^n + 7*R_n - 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

0, 1, 4, 10, 165, 228, 384, 2890, 3445, 10069, 17356, 25804, 29052, 29082 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,3`
	COMMENTS	`Also numbers n such that (25*10^n-43)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 277...773.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(25*10^n - 43)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A203224 A198156 A003086 * A085649 A152396 A048873` `Adjacent sequences: A102955 A102956 A102957 * A102959 A102960 A102961`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 17 2004`
	EXTENSIONS	`Addition of a(10)-a(14) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 12 2010`

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Last modified February 17 18:15 EST 2012. Contains 206061 sequences.