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A271525 Decimal expansion of the real part of the derivative of the Dirichlet function eta(z), at z=i, the imaginary unit. 5
2, 3, 5, 9, 2, 0, 9, 4, 8, 0, 5, 0, 4, 4, 0, 9, 2, 3, 6, 3, 4, 0, 7, 9, 2, 6, 7, 6, 0, 3, 0, 5, 8, 4, 3, 4, 7, 6, 0, 4, 1, 9, 5, 7, 3, 5, 8, 9, 5, 9, 1, 5, 1, 2, 9, 4, 8, 3, 0, 4, 6, 6, 0, 0, 4, 5, 9, 5, 9, 5, 9, 8, 4, 0, 8, 0, 3, 1, 6, 2, 6, 5, 2, 4, 3, 4, 5, 7, 3, 8, 7, 0, 1, 0, 6, 7, 3, 6, 2, 1, 6, 0, 3, 7, 5 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

The corresponding imaginary part of eta'(i) is in A271526.

LINKS

Stanislav Sykora, Table of n, a(n) for n = 0..2000

Eric Weisstein's World of Mathematics, Dirichlet Eta Function

FORMULA

Equals real(eta'(i)).

EXAMPLE

0.235920948050440923634079267603058434760419573589591512948304660...

MATHEMATICA

RealDigits[Re[2^(1-I)*Log[2]*Zeta[I] + (1 - 2^(1-I))*Zeta'[I]], 10, 120][[1]] (* Vaclav Kotesovec, Apr 10 2016 *)

PROG

(PARI) \\ Derivative of Dirichlet eta function (fails for z=1):

derdireta(z)=2^(1-z)*log(2)*zeta(z)+(1-2^(1-z))*zeta'(z);

real(derdireta(I)) \\ Evaluation

CROSSREFS

Cf. A271523 (real(eta(i))), A271524 (imag(eta(i))), A271526(-imag(eta'(i))).

Sequence in context: A279074 A120495 A107477 * A232562 A064358 A109736

Adjacent sequences:  A271522 A271523 A271524 * A271526 A271527 A271528

KEYWORD

nonn,cons

AUTHOR

Stanislav Sykora, Apr 09 2016

STATUS

approved

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Last modified May 23 04:09 EDT 2017. Contains 286909 sequences.