A065357 - OEIS

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A065357

(-1)^pi(n) where pi(n) is the number of primes <= n.

1, 1, -1, 1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, 1, 1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, 1, 1 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,1`
	LINKS	`Harry J. Smith, Table of n, a(n) for n=0,...,1000`
	PROG	`(PARI) { for (n=0, 1000, if (n, a=(-1)^primepi(n), a=1); write("b065357.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 30 2009]`
	CROSSREFS	`Cf. A000720.` `Sequence in context: A143431 A064179 * A121241 A122188 A000012 A158388` `Adjacent sequences: A065354 A065355 A065356 * A065358 A065359 A065360`
	KEYWORD	`easy,sign`
	AUTHOR	`Jason Earls (zevi_35711(AT)yahoo.com), Oct 31 2001`

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Last modified February 17 12:38 EST 2012. Contains 206021 sequences.