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A072986 Least k such that prod( i = 1, k, prime(i)+1)>= n*prod(i = 1, k, prime(i)). 2
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; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..22.

FORMULA

a(n+1)/a(n)->e as n->infinity - Robert Gerbicz, May 09 2008

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}]

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);

CROSSREFS

Sequence in context: A005673 A084308 A067605 * A079047 A160966 A052326

Adjacent sequences:  A072983 A072984 A072985 * A072987 A072988 A072989

KEYWORD

more,nonn

AUTHOR

Benoit Cloitre, Aug 14 2002

EXTENSIONS

Edited and extended by Robert G. Wilson v, Aug 20 2002

6 more terms from Robert Gerbicz, May 09 2008

STATUS

approved

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Last modified July 4 12:18 EDT 2020. Contains 335448 sequences. (Running on oeis4.)