id:A102978 - OEIS Search Results

Search: id:A102978

Displaying 1-1 of 1 results found.

page 1

Numbers n such that 3*10^n + 8*R_n - 7 is a prime, where R_n = 11...1 is the repunit (A002275) of length n.

+0
2

1, 3, 19, 30, 40, 42, 45, 70, 307, 538, 1609, 1668, 1674, 4492, 4935, 6112 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`Also numbers n such that (35*10^n-71)/9 is a prime.`
	LINKS	`Makoto Kamada, Factorizations of 388...881.` `Index entries for primes involving repunits.`
	MATHEMATICA	`Do[ If[ PrimeQ[(35*10^n - 71)/9], Print[n]], {n, 0, 10000}]`
	CROSSREFS	`Sequence in context: A063557 A062619 A108137 this_sequence A107165 A066811 A162307` `Adjacent sequences: A102975 A102976 A102977 this_sequence A102979 A102980 A102981`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 17 2004`

page 1

Search completed in 0.002 seconds

Last modified December 15 00:47 EST 2009. Contains 170825 sequences.