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A057867 Denominator of coefficient of Pi^n in Ramanujan-like series for Zeta[4n+3]. 2
180, 56700, 425675250, 390769879500, 21438612514068750, 1211517431782539131250, 3952575621190533915703125, 28870481903812321637757079687500 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Sum_{k>0} 1/(tanh(k*pi)k^(4n-1)) = pi^(4n-1)*A057866(n)/A057867(n) - Michael Somos Feb 11 2004

REFERENCES

E. C. Titchmarsh, The Theory of Functions, 2nd ed., Oxford Univ. Press, 1939, p. 135.

LINKS

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

EXAMPLE

Sum_{k>0} 1/(tanh(k*pi)k^3) = pi^3*7/180, Sum_{k>0} 1/(tanh(k*pi)k^7) = pi^7*19/56700.

MATHEMATICA

Denominator[Table[2^(k-1)/(k+1)! Sum[(-1)^(n-1)Binomial[k+1, 2n]BernoulliB[k+1-2n]BernoulliB[2n], {n, 0, (k+1)/2}], {k, 3, 50, 4}]]

CROSSREFS

Cf. A057866.

Sequence in context: A035830 A091033 A146530 * A075871 A177327 A074811

Adjacent sequences:  A057864 A057865 A057866 * A057868 A057869 A057870

KEYWORD

nonn

AUTHOR

Eric Weisstein (eric(AT)weisstein.com)

EXTENSIONS

Definition corrected by Tito Piezas III (tpiezas(AT)gmail.com), May 18 2009

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Last modified February 16 04:18 EST 2012. Contains 205860 sequences.