A102989 - OEIS

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A102989

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

1, 3, 5, 6, 8, 15, 26, 53, 60, 97, 183, 205, 302, 396, 456, 467, 607, 828, 1860, 2743, 4273, 4781, 5712, 6038, 6637, 9222, 10832, 18865, 25848 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (13*10^n+11)/3 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 433...337.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(13*10^n + 11)/3], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A039869 A076210 A039014 * A005623 A152989 A195481` `Adjacent sequences: A102986 A102987 A102988 * A102990 A102991 A102992`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 17 2005`
	EXTENSIONS	`Addition of a(27)-a(29) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 08 2010`

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Last modified February 15 23:53 EST 2012. Contains 205860 sequences.