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A112102 Numerator of Sum_{i=1..n} 1/(i^3*C(2*i,i)). 5
0, 1, 25, 1129, 63251, 1581371, 52185743, 33242372291, 24176277773, 40688677687159, 2378722720177, 3741730846458901, 86059809503772983, 72720539036773885963, 72720539038037143387, 52722390802769505531767, 13075152919096992777263341 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
EXAMPLE
0, 1/2, 25/48, 1129/2160, 63251/120960, 1581371/3024000, 52185743/99792000, ... -> Pi^2/18.
MAPLE
f:= proc(n) local i; numer(add(1/(i^3*binomial(2*i, i)), i=1..n)) end proc:
map(f, [$0..20]); # Robert Israel, Jun 22 2023
MATHEMATICA
Join[{0}, Numerator[Accumulate[Table[1/(i^3 Binomial[2i, i]), {i, 20}]]]] (* Harvey P. Dale, May 28 2014 *)
PROG
(PARI) a(n) = numerator(sum(i=1, n, 1/(i^3*binomial(2*i, i)))); \\ Michel Marcus, Mar 10 2016
CROSSREFS
Cf. A086463 (Pi^2/18), A112103 (denominator).
Sequence in context: A066852 A123204 A012508 * A012799 A120694 A012809
KEYWORD
nonn,frac
AUTHOR
N. J. A. Sloane, Nov 30 2005
EXTENSIONS
Definition corrected (and an incorrect sum deleted) by Wolfdieter Lang, Oct 07 2008
STATUS
approved

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Last modified July 18 16:59 EDT 2024. Contains 374388 sequences. (Running on oeis4.)