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 A079780 a(n) = largest prime <= n*prime(n). 2
 2, 5, 13, 23, 53, 73, 113, 151, 199, 283, 337, 443, 523, 601, 701, 839, 997, 1097, 1259, 1409, 1531, 1733, 1907, 2131, 2423, 2621, 2777, 2971, 3137, 3389, 3931, 4177, 4519, 4723, 5209, 5431, 5807, 6173, 6491, 6917, 7333, 7591, 8209, 8467, 8863, 9151, 9907 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) is the largest prime < A079779(n). LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 FORMULA a(n) = prime(A057855(n)). - Michel Marcus, Aug 30 2019 MAPLE With exception of first term: seq(prevprime(n*ithprime(n)), n=2..40); MATHEMATICA PrevPrim[n_] := Block[{k = n - 1}, While[ !PrimeQ[k], k-- ]; k]; Table[ Abs[ PrevPrim[ n*Prime[n]]], {n, 1, 50}] Table[Abs[NextPrime[n Prime[n], -1]], {n, 50}] (* Harvey P. Dale, May 25 2012 *) PROG (PARI) for(n=1, 47, print1(precprime(n*prime(n)), ", ")) CROSSREFS Cf. A057855, A079779. Sequence in context: A256491 A106009 A194552 * A178621 A362105 A309230 Adjacent sequences: A079777 A079778 A079779 * A079781 A079782 A079783 KEYWORD nonn AUTHOR Amarnath Murthy, Feb 03 2003 EXTENSIONS Edited and extended by Robert G. Wilson v, Klaus Brockhaus and Mark Hudson (mrmarkhudson(AT)hotmail.com), Feb 04 2003 STATUS approved

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Last modified September 12 17:49 EDT 2024. Contains 375853 sequences. (Running on oeis4.)