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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, 82125909539251, 9617692012399, 55555555342491359799151, 1116817987709786226917069, 578610396154837, 66992050984853, 254497141, 1660738053545999, 201525986561, 25600818891233, 796725607788661087 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS MATHEMATICA NestWhileList[FactorInteger[2+#*Prime[PrimePi[ # ]-2]][[ -1, 1]] &, 7, True, 8] - T. D. Noe, Nov 15 2006 NestList[FactorInteger[NextPrime[NextPrime[#, -1], -1]#+2][[-1, 1]]&, 7, 20] (* Harvey P. Dale, Dec 26 2017 *) CROSSREFS Cf. A082032, A031441, A031442. Sequence in context: A064640 A064639 A064638 * A227254 A080082 A158954 Adjacent sequences:  A082018 A082019 A082020 * A082022 A082023 A082024 KEYWORD nonn AUTHOR Yasutoshi Kohmoto, May 10 2003 EXTENSIONS Description corrected by Rick L. Shepherd, Dec 19 2004 Corrected by T. D. Noe, Nov 15 2006 More terms from Harvey P. Dale, Dec 26 2017 STATUS approved

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Last modified October 21 08:27 EDT 2018. Contains 316405 sequences. (Running on oeis4.)