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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

Table of n, a(n) for n=1..15.

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

Cf. A088652, A125838, A125839, A088250, A101779.

Sequence in context: A145805 A277192 A098238 * A161019 A137901 A138095

Adjacent sequences:  A088648 A088649 A088650 * A088652 A088653 A088654

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 May 25 19:44 EDT 2019. Contains 323576 sequences. (Running on oeis4.)