A102942 - OEIS

This site is supported by donations to The OEIS Foundation.

A102942

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

1, 2, 8, 26, 44, 167, 185, 3818, 8741 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Also numbers n such that (16*10^n-43)/9 is prime.`
	LINKS	`Makoto Kamada, Factorizations of 177...773.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(16*10^n - 43)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A150672 A150673 A195585 * A206803 A100504 A099416` `Adjacent sequences: A102939 A102940 A102941 * A102943 A102944 A102945`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 16 2004`

Content is available under The OEIS End-User License Agreement .

Last modified February 15 08:07 EST 2012. Contains 205719 sequences.