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A072986
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Least k such that prod( i = 1, k, prime(i)+1)>= n*prod(i = 1, k, prime(i)).
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0
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1, 2, 6, 11, 24, 52, 113, 248, 553, 1245, 2828, 6481, 14963, 34770, 81253, 190836, 450202, 1066269, 2534269, 6042375, 14447465, 34632759
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| a(n+1)/a(n)->e as n->infinity - Robert Gerbicz (robert.gerbicz(AT)gmail.com), May 09 2008
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MATHEMATICA
| a = b = k = 1; Do[ While[a = a*Prime[k]; b = b*(Prime[k] + 1); b < n*a, k++ ]; Print[k]; k++, {n, 1, 16}]
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PROG
| (PARI) a(n)=if(n<0, 0, s=1; while(prod(i=1, s, prime(i)+1)<prod(i=1, s, prime(i))*n, s++); s);
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CROSSREFS
| Sequence in context: A005673 A084308 A067605 * A079047 A160966 A052326
Adjacent sequences: A072983 A072984 A072985 * A072987 A072988 A072989
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KEYWORD
| more,nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 14 2002
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EXTENSIONS
| Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 20 2002
6 more terms from Robert Gerbicz (robert.gerbicz(AT)gmail.com), May 09 2008
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