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A031442 a(0) = 13; for n > 0, a(n) is the greatest prime factor of PreviousPrime(a(n-1))*a(n-1)-1 where PreviousPrime(prime(k))=prime(k-1). 4
13, 71, 41, 379, 23561, 5431, 20269, 89, 1231, 44497, 329952671, 36583, 1126159, 90209117, 14095897, 15272393, 13887359, 256460794943, 2740505805180429880723, 1591234463080874838018721796071210709 (list; graph; refs; listen; history; internal format)
OFFSET

0,1

CROSSREFS

Cf. A031441.

Sequence in context: A085461 A081860 A050403 * A066831 A067382 A158941

Adjacent sequences:  A031439 A031440 A031441 * A031443 A031444 A031445

KEYWORD

nonn

AUTHOR

Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp)

EXTENSIONS

More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), May 23 2000. a(19) and a(20) pass the strong pseudoprime test for many bases.

Edited by T. D. Noe (noe(AT)sspectra.com), Oct 30 2008

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Last modified February 14 06:09 EST 2012. Contains 205570 sequences.