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A088651 a(n) = smallest number k such that rk-1 is prime for all r = 1 to n. 7
3, 3, 4, 6, 6, 154770, 2894220, 2894220, 407874180, 214580145780, 9448481062020, 247236503934420, 2545206711847800, 18178612369988250180, 53792264108455702830 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Is the sequence finite?
LINKS
Carlos Rivera, Problems & Puzzles.
EXAMPLE
a(5)=6 because 1*6-1, 2*6-1, 3*6-1, 4*6-1, 5*6-1 are all prime.
a(11)=9448481062020 because all eleven numbers 1*9448481062020-1, 2*9448481062020-1,3*9448481062020-1,...,10*9448481062020-1 & 11*9448481062020-1 are prime and 9448481062020 is the smallest number with such property.
CROSSREFS
Sequence in context: A145805 A277192 A098238 * A161019 A137901 A138095
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Oct 29 2003
EXTENSIONS
Corrected and extended by Ray Chandler, Nov 01 2003
More terms from Don Reble, Nov 23 2003
Entry revised by N. J. A. Sloane, Jan 05 2007
a(14)-a(15) from Jens Kruse Andersen, May 02 2008
STATUS
approved

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Last modified April 23 14:49 EDT 2024. Contains 371914 sequences. (Running on oeis4.)