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A068205 Denominator of S(n)/Pi^n, where S(n) = Sum((4k+1)^(-n),k,-inf,+inf). 2
4, 8, 32, 96, 1536, 960, 184320, 161280, 8257536, 2903040, 14863564800, 638668800, 1569592442880, 49816166400, 5713316492083200, 83691159552000, 1096956766479974400, 2845499424768000, 6713375410857443328000 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

REFERENCES

N. D. Elkies, On the sums Sum_{k = -infinity .. infinity} (4k+1)^(-n), Amer. Math. Monthly, 110 (No. 7, 2003), 561-573.

LINKS

N. D. Elkies, On the sums Sum((4k+1)^(-n),k,-inf,+inf)

FORMULA

There is a simple formula in terms of Euler and Bernoulli numbers.

EXAMPLE

The first few values of S(n)/Pi^n are 1/4, 1/8, 1/32, 1/96, 5/1536, 1/960, ...

CROSSREFS

Numerators: A050970.

Sequence in context: A149093 A149094 A086344 * A113479 A103970 A034785

Adjacent sequences:  A068202 A068203 A068204 * A068206 A068207 A068208

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Mar 24 2002

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Last modified February 14 17:27 EST 2012. Contains 205644 sequences.