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A257960 Decimal expansion of Sum_{n=3..infinity} (-1)^n/log(log(log(n))). 5
2, 7, 7, 8, 6, 7, 4, 9, 8, 9, 6, 8, 4, 5, 6, 8, 1, 7, 2, 3, 0, 6, 4, 4, 9, 9, 4, 5, 7, 9, 0, 3, 1, 0, 1, 4, 9, 0, 6, 9, 3, 6, 4, 2, 1, 1, 4, 6, 6, 7, 6, 5, 8, 8, 8, 3, 9, 1, 0, 1, 9, 3, 3, 2, 5, 5, 1, 9, 0, 2, 7, 1, 3, 7, 0, 9, 9, 9, 2, 5, 5, 5, 0, 1, 2, 2, 7, 6, 9, 6, 8, 8, 3, 0, 9, 6, 8, 3, 3, 0, 6, 8, 4, 7, 6, 3, 0, 8, 3 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

An extremely slowly convergent series, converging in virtue of Leibniz's rule.

LINKS

Table of n, a(n) for n=3..111.

Eric Weisstein's World of Mathematics, Leibniz Criterion

Wikipedia, Alternating series test

EXAMPLE

277.8674989684568172306449945790310149069364211466765...

MAPLE

evalf(sum((-1)^n/log(log(log(n))), n = 3..infinity), 120); (* Maple 12.0 computes this expression with no problems, but later versions of Maple may have some problems with it *)

MATHEMATICA

N[NSum[(-1)^n/Log[Log[Log[n]]], {n, 3, Infinity}, AccuracyGoal -> 500, Method -> "AlternatingSigns", WorkingPrecision -> 1000], 119] (* Mathematica needs higher precision than usual to compute this series *)

PROG

(PARI) default(realprecision, 200); precision(sumalt(n=3, (-1)^n/log(log(log(n)))), 120) /* PARI needs higher precision than usual to compute this series */

CROSSREFS

Cf. A099769, A257837, A257812, A257898.

Sequence in context: A068386 A021040 A246553 * A238734 A316352 A114532

Adjacent sequences:  A257957 A257958 A257959 * A257961 A257962 A257963

KEYWORD

nonn,cons

AUTHOR

Iaroslav V. Blagouchine, May 14 2015

STATUS

approved

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Last modified August 21 10:21 EDT 2018. Contains 313937 sequences. (Running on oeis4.)