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A130034 Denominators of partial sums of a series for the inverse of the arithmetic-geometric mean (agM) of 1 and sqrt(2)/2. 3
1, 8, 256, 2048, 262144, 2097152, 67108864, 536870912, 274877906944, 2199023255552, 70368744177664, 562949953421312, 72057594037927936, 576460752303423488, 18446744073709551616, 147573952589676412928 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

See the references and the W. Lang link under A129934.

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..665

FORMULA

a(n) = denom(sum((((2*j)!/(j!^2))^2)*(1/2^(5*j)),j=0..n)), n>=0.

MATHEMATICA

Denominator[Table[Sum[(((2*k)!/(k!^2))^2)*(1/2^(5*k)), {k, 0, n}], {n, 0, 50}]] (* G. C. Greubel, Aug 17 2018 *)

PROG

(PARI) for(n=0, 50, print1(denominator(sum(k=0, n, (((2*k)!/(k!^2))^2)*(1/2^(5*k)))), ", ")) \\ G. C. Greubel, Aug 17 2018

CROSSREFS

Sequence in context: A317511 A300176 A291850 * A128787 A013824 A010044

Adjacent sequences:  A130031 A130032 A130033 * A130035 A130036 A130037

KEYWORD

nonn,frac,easy

AUTHOR

Wolfdieter Lang Jun 01 2007

STATUS

approved

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Last modified June 18 04:41 EDT 2021. Contains 345098 sequences. (Running on oeis4.)