A102952 - OEIS

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A102952

Numbers n such that 2*10^n + 4*R_n - 3 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

2, 3, 6, 11, 30, 128, 183, 375, 2159, 2568, 3369, 24989 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Also numbers n such that (22*10^n-31)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 244...441.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(22*10^n - 31)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A115114 A086209 A022490 * A065653 A102021 A144641` `Adjacent sequences: A102949 A102950 A102951 * A102953 A102954 A102955`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 17 2004`
	EXTENSIONS	`Addition of a(12) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 13 2010`

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Last modified February 15 21:56 EST 2012. Contains 205860 sequences.