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A082021 a(0) = 7; for n > 0, a(n) is the greatest prime factor of PP(PP(a(n-1)))*a(n-1)+2 where PP(n) is an abbreviation for PreviousPrime(n). 2
7, 23, 131, 47, 643, 2459, 2000807, 503347241 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..7.

MATHEMATICA

NestWhileList[FactorInteger[2+#*Prime[PrimePi[ # ]-2]][[ -1, 1]] &, 7, True, 8] - T. D. Noe, Nov 15 2006

CROSSREFS

Cf. A082032, A031441, A031442.

Sequence in context: A064640 A064639 A064638 * A080082 A158954 A056205

Adjacent sequences:  A082018 A082019 A082020 * A082022 A082023 A082024

KEYWORD

nonn

AUTHOR

Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp), May 10 2003

EXTENSIONS

Description corrected by Rick L. Shepherd, Dec 19 2004

Corrected by T. D. Noe, Nov 15 2006

STATUS

approved

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Last modified May 23 12:14 EDT 2013. Contains 225587 sequences.