A059457 - OEIS

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A059457

Numerator of sum(k=0,n,(-1)^k/(3k+1)).

1, 3, 25, 111, 1583, 5877, 118943, 1239213, 6500369, 6228669, 200696339, 3293919963, 125884243831, 122175729021, 5401896940303, 121054306890369, 868338554787383, 848589287072283, 867261322002923, 24637097377492167 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	FORMULA	`sum(k>=0, (-1)^k/(3k+1)) = log(2)/3+Pi/3/sqrt(3)`
	PROG	`(PARI) a(n)=numerator(sum(k=0, n, (-1)^k/(3*k+1)))`
	CROSSREFS	`For denominators see A051536.` `Sequence in context: A124245 A166899 A201534 * A165206 A095664 A099868` `Adjacent sequences: A059454 A059455 A059456 * A059458 A059459 A059460`
	KEYWORD	`frac,nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 19 2002`
	EXTENSIONS	`Corrected by T. D. Noe (noe(AT)sspectra.com), Oct 25 2006`

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Last modified February 17 21:13 EST 2012. Contains 206085 sequences.