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A160759 Integer averages of n values of pi(n^2) for some n, where pi(n) is the number of primes <= n. 0
0, 1, 2, 3, 201, 235, 265, 431, 1705, 11744, 33946, 622755, 3446493, 8134880, 14287916, 208340425, 223689468 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

For values of n: 1, 2, 3, 4, 62, 68, 73, 97, 213, 624, 1116, 5364, 13350, 21048, 28351, 116151, 120562, ..., . [Robert G. Wilson v, Jun 05 2009]

LINKS

Table of n, a(n) for n=1..17.

FORMULA

1/k*Sum {j=1..k} Pi(j^2) is an integer. [Robert G. Wilson v, Jun 05 2009]

MATHEMATICA

lst = {}; s = 0; k = 1; While[k < 239600, s = s + PrimePi[k^2]; If[ Mod[s, k] == 0, AppendTo[lst, s/c]]; k++ ]; lst (* Robert G. Wilson v, Jun 05 2009 *)

CROSSREFS

Cf. A050248, Integer averages of n primes for some n.

Sequence in context: A106817 A233318 A231387 * A191835 A195264 A037274

Adjacent sequences:  A160756 A160757 A160758 * A160760 A160761 A160762

KEYWORD

nonn,more

AUTHOR

Daniel Tisdale, May 25 2009

EXTENSIONS

More terms from Robert G. Wilson v, Jun 05 2009

STATUS

approved

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Last modified February 19 12:48 EST 2018. Contains 299333 sequences. (Running on oeis4.)