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Search: id:A079780
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| A079780 |
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a(n) = largest prime <= n*prime(n). |
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+0
2
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| 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; listen)
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OFFSET
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1,1
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MAPLE
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With exception of first term: seq(prevprime(n*ithprime(n)), n=2..40);
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MATHEMATICA
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PrevPrim[n_] := Block[{k = n - 1}, While[ !PrimeQ[k], k-- ]; k]; Table[ Abs[ PrevPrim[ n*Prime[n]]], {n, 1, 50}]
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PROGRAM
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(PARI) for(n=1, 47, print1(precprime(n*prime(n)), ", "))
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CROSSREFS
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Cf. A079779.
a(n) is the largest prime < A079779(n).
Sequence in context: A075470 A049779 A106009 this_sequence A048871 A072921 A087250
Adjacent sequences: A079777 A079778 A079779 this_sequence A079781 A079782 A079783
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Feb 03 2003
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Mark Hudson (mrmarkhudson(AT)hotmail.com), Feb 04 2003
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