A086467 - OEIS

A086467

Decimal expansion of 2*arccsch(2)^2.

4, 6, 3, 1, 2, 9, 6, 4, 1, 1, 5, 4, 3, 8, 8, 7, 8, 4, 9, 9, 3, 8, 5, 8, 1, 4, 2, 4, 6, 3, 0, 6, 5, 5, 2, 0, 0, 3, 2, 8, 1, 2, 7, 0, 0, 0, 9, 8, 5, 9, 7, 7, 4, 1, 6, 3, 0, 6, 0, 2, 4, 5, 7, 3, 7, 9, 5, 9, 0, 6, 9, 1, 1, 3, 3, 9, 2, 3, 6, 2, 5, 9, 7, 0, 1, 0, 9, 0, 9, 4, 1, 7, 2, 7, 7, 6, 7, 9, 0, 1, 1, 1

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OFFSET

0,1

LINKS

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

Steven R. Finch, Mathematical Constants II, Encyclopedia of Mathematics and Its Applications, Cambridge University Press, Cambridge, 2018, p. 77.

Renzo Sprugnoli, Sums of reciprocals of the central binomial coefficients, INTEGERS 6 (2006) #A27

Eric Weisstein's World of Mathematics, Central Binomial Coefficient

FORMULA

Equals Sum_{n>=1} (-1)^(n-1)/n^2/binomial(2*n,n).

Equals Integral_{x=0..1} log(1+x-x^2)/x dx. - Vaclav Kotesovec, Jun 13 2021

Equals 2*A002390^2. - R. J. Mathar, Jun 07 2024