A102974 - OEIS

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A102974

Numbers n such that 3*10^n + 6*R_n - 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

0, 1, 6, 11, 13, 19, 23, 67, 108, 118, 176, 673, 780, 1088, 1219, 1656, 6245, 10739, 12590, 17513, 26000 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,3`
	COMMENTS	`Also numbers n such that (11*10^n-17)/3 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 366...661.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(11*10^n-17)/3], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A175021 A046953 A121765 * A154293 A199717 A068308` `Adjacent sequences: A102971 A102972 A102973 * A102975 A102976 A102977`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 17 2004`
	EXTENSIONS	`Addition of a(18)-a(21) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 10 2010`

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Last modified February 17 10:05 EST 2012. Contains 206009 sequences.