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A124478 Let p(n) = prime(n); sequence gives p(n) - floor( (2/n)*(Sum_{i=1..n} p(i)) ). +0
1
-2, -2, -1, -1, 0, 0, 1, 0, 1, 4, 2, 5, 5, 3, 4, 6, 8, 6, 8, 8, 6, 8, 7, 9, 13, 12, 10, 10, 7, 7, 17, 16, 17, 14, 19, 17, 18, 19, 18, 19, 20, 17, 22, 19, 18, 16, 23, 29, 28, 25, 24, 25, 21, 26, 27, 28, 28, 25, 26, 25, 22, 27, 35, 34, 30, 29, 37, 38, 42, 38, 37, 37, 40, 40, 40, 39, 39, 41, 40, 42 (list; graph; listen)
OFFSET

1,1

COMMENT

Robert Mandl conjectured and Rosser and Schoenfeld proved that p(n)/2 > (Sum_{i=1..n} p(i))/n for n >= 9 (implying that a(n) > 0 for n >= 9).

REFERENCES

Rosser, J. Barkley; and Schoenfeld, Lowell; Sharper bounds for the Chebyshev functions theta(x) and psi(x), Math. Comp. 29 (1975), 243-269.

LINKS

Zak Seidov, Table of n, a(n) for n = 1..1000.

Pierre Dusart, Autour de la fonction qui compte le nombre de nombres premiers, Th\`ese, Universit\'e de Limoges, France, (1998), see Section 1.9.

M. Hassani, A Remark on the Mandl's Inequality.

CROSSREFS

Sequence in context: A054924 A025485 A046751 this_sequence A030353 A089617 A128521

Adjacent sequences: A124475 A124476 A124477 this_sequence A124479 A124480 A124481

KEYWORD

sign

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Dec 17 2006

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Last modified November 23 17:09 EST 2009. Contains 167438 sequences.


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