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A059457 Numerator of Sum_{k=0..n} (-1)^k/(3*k+1). 2
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; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

FORMULA

Sum_{k>=0} (-1)^k/(3*k+1) = (log(2)*sqrt(3) + Pi)/(3*sqrt(3)).

MATHEMATICA

Table[Numerator[Sum[(-1)^k/(3*k + 1), {k, 0, n}]], {n, 0, 50}] (* G. C. Greubel, Oct 04 2017 *)

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 A215773

Adjacent sequences:  A059454 A059455 A059456 * A059458 A059459 A059460

KEYWORD

frac,nonn

AUTHOR

Benoit Cloitre, Oct 19 2002

EXTENSIONS

Corrected by T. D. Noe, Oct 25 2006

STATUS

approved

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Last modified May 19 05:05 EDT 2019. Contains 323377 sequences. (Running on oeis4.)