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A086466 Decimal expansion of 2*sqrt(5)/5 arccsch(2). 10
4, 3, 0, 4, 0, 8, 9, 4, 0, 9, 6, 4, 0, 0, 4, 0, 3, 8, 8, 8, 9, 4, 3, 3, 2, 3, 2, 9, 5, 0, 6, 0, 5, 4, 2, 5, 4, 2, 4, 5, 7, 0, 6, 8, 2, 5, 4, 0, 2, 8, 9, 6, 5, 4, 7, 5, 7, 0, 0, 6, 1, 0, 3, 9, 9, 2, 5, 6, 1, 2, 1, 5, 4, 6, 1, 1, 3, 1, 9, 6, 1, 3, 6, 1, 4, 9, 0, 2, 6, 4, 6, 9, 7, 2, 1, 9, 9, 5, 5, 4, 0, 6 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..101.

Eric Weisstein's World of Mathematics, Central Binomial Coefficient

FORMULA

Equals sum(n>=1, (-1)^(n-1)/n/binomial(2*n,n) ).

Equals A010532 * A002390 / 10. - R. J. Mathar, Jul 26 2010

Also equals f'(0) = 2*log(phi)/sqrt(5), with f(x) = (phi^x-cos(Pi*x)*phi^-x)/sqrt(5), the real Fibonacci interpolating function. - Jean-François Alcover, Apr 04 2014

EXAMPLE

0.43040894096400403888943323295060542542457...

MATHEMATICA

2*Log[GoldenRatio]/Sqrt[5] // RealDigits[#, 10, 102]& // First (* Jean-François Alcover, Apr 18 2014 *)

CROSSREFS

Cf. A086465, A086467, A086468.

Sequence in context: A296228 A267410 A016697 * A204694 A242721 A251610

Adjacent sequences:  A086463 A086464 A086465 * A086467 A086468 A086469

KEYWORD

nonn,cons

AUTHOR

Eric W. Weisstein, Jul 21 2003

STATUS

approved

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Last modified February 21 02:19 EST 2018. Contains 299388 sequences. (Running on oeis4.)