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A122214 Numerators in infinite products for Pi/2, e, and e^gamma (reduced). +0
6
1, 2, 4, 32, 4096, 67108864, 4503599627370496, 2535301200456458802993406410752, 4084620902943761579745625423246687265522976897405582347410338578593480704 (list; graph; listen)
OFFSET

1,2

REFERENCES

J. Sondow, A faster product for Pi and a new integral for ln Pi/2, Amer. Math. Monthly 112 (2005) 729-734.

LINKS

J. Baez, This Week's Finds in Mathematical Physics

J. Guillera and J. Sondow, Double integrals and infinite products for some classical constants via analytic continuations of Lerch's transcendent

FORMULA

a(n) = numerator(product(k = 1...n, k^((-1)^k*binomial(n-1,k-1)))).

EXAMPLE

Pi/2 = (2/1)^(1/2) * (4/3)^(1/4) * (32/27)^(1/8) * (4096/3645)^(1/16) * ...,

e = (2/1)^(1/1) * (4/3)^(1/2) * (32/27)^(1/3) * (4096/3645)^(1/4) * ... and

e^gamma = (2/1)^(1/2) * (4/3)^(1/3) * (32/27)^(1/4) * (4096/3645)^(1/5) * ....

CROSSREFS

Cf. A092798. Denominators are A122215. Unreduced numerators are A122216.

Adjacent sequences: A122211 A122212 A122213 this_sequence A122215 A122216 A122217

Sequence in context: A101460 A118992 A062740 this_sequence A122216 A100117 A073888

KEYWORD

frac,nonn

AUTHOR

Jonathan Sondow (jsondow(AT)alumni.princeton.edu), Aug 26 2006

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Last modified May 17 13:36 EDT 2008. Contains 139908 sequences.


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